利用公式“(x+a)(x+b)=x^2+(a+b)x+ab”计算
问题描述:
利用公式“(x+a)(x+b)=x^2+(a+b)x+ab”计算
(1)(x+1)(x+3);(2)(a-2)(a-5);(3)(a-2)(a+2);(4)(m+2)(m-3);(5)(ab-2)(ab+1);(6)(x-2y)(x+3y)
答
(1)(x+1)(x+3)=x²+4x+3(2)(a-2)(a-5)=a²-7a+10(3)(a-2)(a+2)=a²-4(4)(m+2)(m-3)=m²-m-6(5)(ab-2)(ab+1)=a²b²-ab-2(6)(x-2y)(x+3y)=x²+xy-6y...