忙しい人のための中学数学【式の展開の解答／前編】

　解答は少しずつ追加していきます！

　単項式×多項式、多項式×単項式、多項式×多項式の問題編はこちら↓

　乗法の公式を用いる計算問題はこちら↓

　その他の単元や計算問題は、リンク集からどうぞ↓

単項式×多項式、多項式×単項式　・・・計80問

A（20問）

① x(2x+3y)
=2x²+3xy

② 2x(3x+4y)
=6x²+8xy

③ 3x(4x+5y)
=12x²+15xy

④ 4x(5x+6y)
=20x²+24xy

⑤ 5x(6x+7y)
=30x²+35xy

⑥ 6x(7x+8y)
=42x²+48xy

⑦ 7x(8x+9y)
=56x²+63xy

⑧ 8x(9x+10y)
=72x²+80xy

⑨ 9x(10x+11y)
=90x²+99xy

⑩ 10x(11x+12y)
=110x²+120xy

⑪ (a+b)×2a
=2a²+2ab

⑫ (2a+2b)×3a
=6a²+6ab

⑬ (3a+3b)×4a
=12a²+12ab

⑭ (4a+4b)×5a
=20a²+20ab

⑮ (5a+5b)×6a
=30a²+30ab

⑯ (6a+6b)×7a
=42a²+42ab

⑰ (7a+7b)×8a
=56a²+56ab

⑱ (8a+8b)×9a
=72a²+72ab

⑲ (9a+9b)×10a
=90a²+90ab

⑳ (10a+10b)×11a
=110a²+110ab

B（20問）

① −x(3x+4y)
=−3x²−4xy

② −2x(4x+5y)
=−8x²−10xy

③ −3x(5x+6y)
=−15x²−18xy

④ −4x(6x+7y)
=−24x²−28xy

⑤ −5x(7x+8y)
=−35x²−40xy

⑥ −6x(8x+9y)
=−48x²−54xy

⑦ −7x(9x+10y)
=−63x²−70xy

⑧ −8x(10x+11y)
=−80x²−88xy

⑨ −9x(11x+12y)
=−99x²−108xy

⑩ −10x(12x+13y)
=−120x²−130xy

⑪ (a+b)×(−3a)
=−3a²−3ab

⑫ (2a+2b)×(−4a)
=−8a²−8ab

⑬ (3a+3b)×(−5a)
=−15a²−15ab

⑭ (4a+4b)×(−6a)
=−24a²−24ab

⑮ (5a+5b)×(−7a)
=−35a²−35ab

⑯ (6a+6b)×(−8a)
=−48a²−48ab

⑰ (7a+7b)×(−9a)
=−63a²−63ab

⑱ (8a+8b)×(−10a)
=−80a²−80ab

⑲ (9a+9b)×(−11a)
=−99a²−99ab

⑳ (10a+10b)×(−12a)
=−120a²−120ab

C（20問）

① x(4x−5y)
=4x²−5xy

② 2x(5x−6y)
=10x²−12xy

③ 3x(6x−7y)
=18x²−21xy

④ 4x(7x−8y)
=28x²−32xy

⑤ 5x(8x−9y)
=40x²−45xy

⑥ 6x(9x−10y)
=54x²−60xy

⑦ 7x(10x−11y)
=70x²−77xy

⑧ 8x(11x−12y)
=88x²−96xy

⑨ 9x(12x−13y)
=108x²−117xy

⑩ 10x(13x−14y)
=130x²−140xy

⑪ (a−b)×4a
=4a²−4ab

⑫ (2a−2b)×5a
=10a²−10ab

⑬ (3a−3b)×6a
=18a²−18ab

⑭ (4a−4b)×7a
=28a²−28ab

⑮ (5a−5b)×8a
=40a²−40ab

⑯ (6a−6b)×9a
=54a²−54ab

⑰ (7a−7b)×10a
=70a²−70ab

⑱ (8a−8b)×11a
=88a²−88ab

⑲ (9a−9b)×12a
=108a²−108ab

⑳ (10a−10b)×13a
=130a²−130ab

D（20問）

① −x(−x+3y)
=x²−3xy

② −2x(−3x+5y)
=6x²−10xy

③ −3x(−5x+7y)
=15x²−21xy

④ −4x(−7x+9y)
=28x²−36xy

⑤ −5x(−9x+11y)
=45x²−55xy

⑥ −6x(−11x+13y)
=66x²−78xy

⑦ −7x(−13x+15y)
=91x²−105xy

⑧ −8x(−15x+y)
=120x²−8xy

⑨ −9x(−x+3y)
=9x²−27xy

⑩ −10x(−3x+5y)
=30x²−50xy

⑪ (−2a+4b)×(−a)
=2a²−4ab

⑫ (−4a+6b)×(−2a)
=8a²−12ab

⑬ (−6a+8b)×(−3a)
=18a²−24ab

⑭ (−8a+10b)×(−4a)
=32a²−40ab

⑮ (−10a+12b)×(−5a)
=50a²−60ab

⑯ (−12a+14b)×(−6a)
=72a²−84ab

⑰ (−14a+2b)×(−7a)
=98a²−14ab

⑱ (−2a+4b)×(−8a)
=16a²−32ab

⑲ (−4a+6b)×(−9a)
=36a²−54ab

⑳ (−6a+8b)×(−10a)
=60a²−80ab

多項式の乗法　(a+b)(c+d)　・・・計60問

A（20問）

① (x+1)(y+2)
=xy+2x+y+2

② (x+2)(y+3)
=xy+3x+2y+6

③ (x+3)(y+4)
=xy+4x+3y+12

④ (x+4)(y+5)
=xy+5x+4y+20

⑤ (x+5)(y+6)
=xy+6x+5y+30

⑥ (x+6)(y+7)
=xy+7x+6y+42

⑦ (x+7)(y+8)
=xy+8x+7y+56

⑧ (x+8)(y+9)
=xy+9x+8y+72

⑨ (x+9)(y+10)
=xy+10x+9y+90

⑩ (x+10)(y+11)
=xy+11x+10y+110

⑪ (a+1)(b+3)
=ab+3a+b+3

⑫ (a+2)(b+4)
=ab+4a+2b+8

⑬ (a+3)(b+5)
=ab+5a+3b+15

⑭ (a+4)(b+6)
=ab+6a+4b+24

⑮ (a+5)(b+7)
=ab+7a+5b+35

⑯ (a+6)(b+8)
=ab+8a+6b+48

⑰ (a+7)(b+9)
=ab+9a+7b+63

⑱ (a+8)(b+10)
=ab+10a+8b+80

⑲ (a+9)(b+11)
=ab+11a+9b+99

⑳ (a+10)(b+12)
=ab+12a+10b+120

B（20問）

① (x+1)(y+4)
=xy+4x+y+4

② (x+2)(y+5)
=xy+5x+2y+10

③ (x+3)(y+6)
=xy+6x+3y+18

④ (x+4)(y+7)
=xy+7x+4y+28

⑤ (x+5)(y+8)
=xy+8x+5y+40

⑥ (x+6)(y+9)
=xy+9x+6y+54

⑦ (x+7)(y+10)
=xy+10x+7y+70

⑧ (x+8)(y+11)
=xy+11x+8y+88

⑨ (x+9)(y+12)
=xy+12x+9y+108

⑩ (x+10)(y+13)
=xy+13x+10y+130

⑪ (a+1)(b+5)
=ab+5a+b+5

⑫ (a+2)(b+6)
=ab+6a+2b+12

⑬ (a+3)(b+7)
=ab+7a+3b+21

⑭ (a+4)(b+8)
=ab+8a+4b+32

⑮ (a+5)(b+9)
=ab+9a+5b+45

⑯ (a+6)(b+10)
=ab+10a+6b+60

⑰ (a+7)(b+11)
=ab+11a+7b+77

⑱ (a+8)(b+12)
=ab+12a+8b+96

⑲ (a+9)(b+13)
=ab+13a+9b+117

⑳ (a+10)(b+14)
=ab+14a+10b+140

C（20問）

① (x+1)(y+6)
=xy+6x+y+6

② (x+2)(y+7)
=xy+7x+2y+14

③ (x+3)(y+8)
=xy+8x+3y+24

④ (x+4)(y+9)
=xy+9x+4y+36

⑤ (x+5)(y+10)
=xy+10x+5y+50

⑥ (x+6)(y+11)
=xy+11x+6y+66

⑦ (x+7)(y+12)
=xy+12x+7y+84

⑧ (x+8)(y+13)
=xy+13x+8y+104

⑨ (x+9)(y+14)
=xy+14x+9y+126

⑩ (x+10)(y+15)
=xy+15x+10y+150

⑪ (a+1)(b+7)
=ab+7a+b+7

⑫ (a+2)(b+8)
=ab+8a+2b+16

⑬ (a+3)(b+9)
=ab+9a+3b+27

⑭ (a+4)(b+10)
=ab+10a+4b+40

⑮ (a+5)(b+11)
=ab+11a+5b+55

⑯ (a+6)(b+12)
=ab+12a+6b+72

⑰ (a+7)(b+13)
=ab+13a+7b+91

⑱ (a+8)(b+14)
=ab+14a+8b+112

⑲ (a+9)(b+15)
=ab+15a+9b+135

⑳ (a+1)(b+8)
=ab+8a+b+8

多項式の乗法　(a−b)(c−d)　・・・計60問

A（20問）

① (x−1)(y−2)
=xy−2x−y+2

② (x−2)(y−3)
=xy−3x−2y+6

③ (x−3)(y−4)
=xy−4x−3y+12

④ (x−4)(y−5)
=xy−5x−5y+20

⑤ (x−5)(y−6)
=xy−6x−5y+30

⑥ (x−6)(y−7)
=xy−7x−6y+42

⑦ (x−7)(y−8)
=xy−8x−7y+56

⑧ (x−8)(y−9)
=xy−9x−8y+72

⑨ (x−9)(y−10)
=xy−10x−9y+90

⑩ (x−10)(y−11)
=xy−11x−10y+110

⑪ (a−1)(b−3)
=ab−3a−b+3

⑫ (a−2)(b−4)
=ab−4a−2b+8

⑬ (a−3)(b−5)
=ab−5a−3b+15

⑭ (a−4)(b−6)
=ab−6a−4b+24

⑮ (a−5)(b−7)
=ab−7a−5b+35

⑯ (a−6)(b−8)
=ab−8a−6b+48

⑰ (a−7)(b−9)
=ab−9a−7b+63

⑱ (a−8)(b−10)
=ab−10a−8b+80

⑲ (a−9)(b−11)
=ab−11a−9b+99

⑳ (a−10)(b−12)
=ab−12a−10b+120

B（20問）

① (x−1)(y−4)
=xy−4x−y+4

② (x−2)(y−5)
=xy−5x−2y+10

③ (x−3)(y−6)
=xy−6x−3y+18

④ (x−4)(y−7)
=xy−7x−4y+28

⑤ (x−5)(y−8)
=xy−8x−5y+40

⑥ (x−6)(y−9)
=xy−9x−6y+54

⑦ (x−7)(y−10)
=xy−10x−7y+70

⑧ (x−8)(y−11)
=xy−11x−8y+88

⑨ (x−9)(y−12)
=xy−12x−9y+108

⑩ (x−10)(y−13)
=xy−13x−10y+130

⑪ (a−1)(b−5)
=ab−5a−b+5

⑫ (a−2)(b−6)
=ab−6a−2b+12

⑬ (a−3)(b−7)
=ab−7a−3b+21

⑭ (a−4)(b−8)
=ab−8a−4b+32

⑮ (a−5)(b−9)
=ab−9a−5b+45

⑯ (a−6)(b−10)
=ab−10a−6b+60

⑰ (a−7)(b−11)
=ab−11a−7b+11

⑱ (a−8)(b−12)
=ab−12a−8b+96

⑲ (a−9)(b−13)
=ab−13a−9b+117

⑳ (a−10)(b−14)
=ab−14a−10b+140

C（20問）

① (x−1)(y−6)
=xy−6x−y+6

② (x−2)(y−7)
=xy−7x−2y+14

③ (x−3)(y−8)
=xy−8x−3y+24

④ (x−4)(y−9)
=xy−9x−4y+36

⑤ (x−5)(y−10)
=xy−10x−5y+50

⑥ (x−6)(y−11)
=xy−11x−6y+66

⑦ (x−7)(y−12)
=xy−12x−7y+84

⑧ (x−8)(y−13)
=xy−13x−8y+104

⑨ (x−9)(y−14)
=xy−14x−9y+126

⑩ (x−10)(y−15)
=xy−15x−10y+150

⑪ (a−1)(b−7)
=ab−7a−b+7

⑫ (a−2)(b−8)
=ab−8a−2b+16

⑬ (a−3)(b−9)
=ab−9a−3b+27

⑭ (a−4)(b−10)
=ab−10a−4b+40

⑮ (a−5)(b−11)
=ab−11a−5b+55

⑯ (a−6)(b−12)
=ab−12a−6b+72

⑰ (a−7)(b−13)
=ab−13a−7b+91

⑱ (a−8)(b−14)
=ab−14a−8b+112

⑲ (a−9)(b−15)
=ab−15a−9b+135

⑳ (a−1)(b−8)
=ab−8a−b+8

多項式の乗法　(a+b)(c−d)　・・・計60問

A（20問）

① (x+1)(y−2)
=xy−2x+y−2

② (x+2)(y−3)
=xy−3x+2y−6

③ (x+3)(y−4)
=xy−4x+3y−12

④ (x+4)(y−5)
=xy−5x+4y−20

⑤ (x+5)(y−6)
=xy−6x+5y−30

⑥ (x+6)(y−7)
=xy−7x+6y−42

⑦ (x+7)(y−8)
=xy−8x+7y−56

⑧ (x+8)(y−9)
=xy−9x+8y−72

⑨ (x+9)(y−10)
=xy−10x+9y−90

⑩ (x+10)(y−11)
=xy−11x+10y−110

⑪ (a+1)(b−3)
=ab−3a+b−3

⑫ (a+2)(b−4)
=ab−4a+2b−8

⑬ (a+3)(b−5)
=ab−5a+3b−15

⑭ (a+4)(b−6)
=ab−6a+4b−24

⑮ (a+5)(b−7)
=ab−7a+5b−35

⑯ (a+6)(b−8)
=ab−8a+6b−48

⑰ (a+7)(b−9)
=ab−9a+7b−63

⑱ (a+8)(b−10)
=ab−10a+8b−80

⑲ (a+9)(b−11)
=ab−11a+9b−99

⑳ (a+10)(b−12)
=ab−12a+10b−120

B（20問）

① (x+1)(y−4)
=xy−4x+y−4

② (x+2)(y−5)
=xy−5x+2y−10

③ (x+3)(y−6)
=xy−6x+3y−18

④ (x+4)(y−7)
=xy−7x+4y−28

⑤ (x+5)(y−8)
=xy−8x+5y−40

⑥ (x+6)(y−9)
=xy−9x+6y−54

⑦ (x+7)(y−10)
=xy−10x+7y−70

⑧ (x+8)(y−11)
=xy−11x+8y−88

⑨ (x+9)(y−12)
=xy−12x+9y−108

⑩ (x+10)(y−13)
=xy−13x+10y−130

⑪ (a+1)(b−5)
=ab−5a+b−5

⑫ (a+2)(b−6)
=ab−6a+2b−12

⑬ (a+3)(b−7)
=ab−7a+3b−21

⑭ (a+4)(b−8)
=ab−8a+4b−32

⑮ (a+5)(b−9)
=ab−9a+5b−45

⑯ (a+6)(b−10)
=ab−10a+6b−60

⑰ (a+7)(b−11)
=ab−11a+7b−77

⑱ (a+8)(b−12)
=ab−12a+8b−96

⑲ (a+9)(b−13)
=ab−13a+9b−117

⑳ (a+10)(b−14)
=ab−14a+10b−140

C（20問）

① (x+1)(y−6)
=xy−6x+y−6

② (x+2)(y−7)
=xy−7x+2y−14

③ (x+3)(y−8)
=xy−8x+3y−24

④ (x+4)(y−9)
=xy−9x+4y−36

⑤ (x+5)(y−10)
=xy−10x+5y−50

⑥ (x+6)(y−11)
=xy−11x+6y−66

⑦ (x+7)(y−12)
=xy−12x+7y−84

⑧ (x+8)(y−13)
=xy−13x+8y−104

⑨ (x+9)(y−14)
=xy−14x+9y−126

⑩ (x+10)(y−15)
=xy−15x+10y−150

⑪ (a+1)(b−7)
=ab−7a+b−7

⑫ (a+2)(b−8)
=ab−8a+2b−16

⑬ (a+3)(b−9)
=ab−9a+3b−24

⑭ (a+4)(b−10)
=ab−10a+4b−40

⑮ (a+5)(b−11)
=ab−11a+5b−55

⑯ (a+6)(b−12)
=ab−12a+6b−72

⑰ (a+7)(b−13)
=ab−13a+7b−91

⑱ (a+8)(b−14)
=ab−14a+8b−112

⑲ (a+9)(b−15)
=ab−15a+9b−135

⑳ (a+1)(b−8)
=ab−8a+b−8

多項式の乗法　(a−b)(c+d)　・・・計60問

A（20問）

① (x−1)(y+2)
=xy+2x−y−2

② (x−2)(y+3)
=xy+3x−2y−6

③ (x−3)(y+4)
=xy+4x−3y−12

④ (x−4)(y+5)
=xy+5x−4y−20

⑤ (x−5)(y+6)
=xy+6x−5y−30

⑥ (x−6)(y+7)
=xy+7x−6y−42

⑦ (x−7)(y+8)
=xy+8x−7y−56

⑧ (x−8)(y+9)
=xy+9x−8y−72

⑨ (x−9)(y+10)
=xy+10x−9y−90

⑩ (x−10)(y+11)
=xy+11x−10y−110

⑪ (a−1)(b+3)
=ab+3a−b−3

⑫ (a−2)(b+4)
=ab+4a−2b−8

⑬ (a−3)(b+5)
=ab+5a−3b−15

⑭ (a−4)(b+6)
=ab+6a−4b−24

⑮ (a−5)(b+7)
=ab+7a−5b−35

⑯ (a−6)(b+8)
=ab+8a−6b−48

⑰ (a−7)(b+9)
=ab+9a−7b−63

⑱ (a−8)(b+10)
=ab+10a−8b−80

⑲ (a−9)(b+11)
=ab+11a−9b−99

⑳ (a−10)(b+12)
=ab+12a−10b−120

B（20問）

① (x−1)(y+4)
=xy+4x−y−4

② (x−2)(y+5)
=xy+5x−2y−10

③ (x−3)(y+6)
=xy+6x−3y−18

④ (x−4)(y+7)
=xy+7x−4y−28

⑤ (x−5)(y+8)
=xy+8x−5y−40

⑥ (x−6)(y+9)
=xy+9x−6y−54

⑦ (x−7)(y+10)
=xy+10x−7y−70

⑧ (x−8)(y+11)
=xy+11x−8y−88

⑨ (x−9)(y+12)
=xy+12x−9y−108

⑩ (x−10)(y+13)
=xy+13x−10y−130

⑪ (a−1)(b+5)
=ab+5a−b−5

⑫ (a−2)(b+6)
=ab+6a−2b−12

⑬ (a−3)(b+7)
=ab+7a−3b−21

⑭ (a−4)(b+8)
=ab+8a−4b−32

⑮ (a−5)(b+9)
=ab+9a−5b−45

⑯ (a−6)(b+10)
=ab+10a−6b−60

⑰ (a−7)(b+11)
=ab+11a−7b−77

⑱ (a−8)(b+12)
=ab+12a−8b−96

⑲ (a−9)(b+13)
=ab+13a−9b−117

⑳ (a−10)(b+14)
=ab+14a−10b−140

C（20問）

① (x−1)(y+6)
=xy+6x−y−6

② (x−2)(y+7)
=xy+7x−2y−14

③ (x−3)(y+8)
=xy+8x−3y−24

④ (x−4)(y+9)
=xy+9x−4y−36

⑤ (x−5)(y+10)
=xy+10x−5y−50

⑥ (x−6)(y+11)
=xy+11x−6y−66

⑦ (x−7)(y+12)
=xy+12x−7y−84

⑧ (x−8)(y+13)
=xy+13x−8y−104

⑨ (x−9)(y+14)
=xy+14x−9y−126

⑩ (x−10)(y+15)
=xy+15x−10y−150

⑪ (a−1)(b+7)
=ab+7a−b−7

⑫ (a−2)(b+8)
=ab+8a−2b−16

⑬ (a−3)(b+9)
=ab+9a−3b−27

⑭ (a−4)(b+10)
=ab+10a−4b−40

⑮ (a−5)(b+11)
=ab+11a−5b−55

⑯ (a−6)(b+12)
=ab+12a−6b−72

⑰ (a−7)(b+13)
=ab+13a−7b−91

⑱ (a−8)(b+14)
=ab+14a−8b−112

⑲ (a−9)(b+15)
=ab+15a−9b−135

⑳ (a−1)(b+8)
=ab+8a−b−8