Question

因式分解x²+4x-xy-2y+4

Answer 1

x^3-x2-4x+4 =x2(x-1)-4(x-1) =(x-1)(x2-1） =(x-1)2(x+1) x2y2-4+xy2-2y =(xy+2)(xy-2)+y(xy-2) =(xy-2)(xy+y+2) （2ab-a2）+（c2-b2） =2ab-a2-b2+c2 =c2-(a-b)2 =(c+a-b)(c-a+b) 已知a-b=2c,求a^3-ab2-4abc-4ac2的值 a-b=2c a=b+2c a^3-ab2-4abc-4ac2 =a(a-b)(a+b)-4ac(b+c) =2ac(a+b)-4ac(b+c) =2ac(b+2c+b)-4ac(b+c) =4ac(b+c)-4ac(b+c) =0