乗法公式2 (x+a)2 = x2+2ax+a2
乗法公式3 (x-a)2 = x2-2ax+a2
(x+5)2
(x-4)2
(2x+3)2
(6x-7y)2
解説動画 ≫
(x+5)2
= x2+2×5×x+52
= x2+10x+25
(x-4)2
= x2-2×4×x+42
= x2-8x+16
(2x+3)2
= (2x)2+2×3×2x+32
= 4x2+12x+9
(6x-7y)2
= (6x)2-2×7y×6x+(7y)2
= 36x2-84xy+49y2
【練習】
(a+3)2
a2+6a+9(x-11)2
x2-22x+121(2x+5)2
4x2+20x+25(3a-4b)2
9a2-24ab+16b2