Question

因式分解9a²(x-y)+4b²(y-x)和(x-1)(x+4)-36谢谢

9a²(x-y)+4b²(y-x)

Answer 1

1. 9a²(x-y) + 4b²(y-x)

   =(3a)²(x-y) - (2b)²(x-y)

   =[(3a)² - (2b)²](x-y)

   =(3a+2b)(3a-2b)(x-y)

2. (x-1)(x+4) - 36

   =(x²-x +4x -4) - 36

   =(x²+3x-4) - 36

   =x²+3x-40

   =x²+(8-5)x - 8×(-5)

   =(x+8)(x-5)