Question

求两道因式分解题已知x-y=2,x^-y^=6.求x,y的值9(2a+3b)^-25(3a-b)^

Answer 1

1)x^-y^=(x+y)(x-y)=6

将（x-y）= 2代入

得到x+y=3 (1)

x-y= 2 (2)

(1) + (2):x=2.5,y=0.5

2)原式=[3(2a+3b)]^ -[5(3a-b)]^

=[3(2a+3b)+5(3a-b)][3(2a+3b)-5(3a-b)]

=(6a+9b+15a-5b)(6a+9b-15a+5b)

=(21a+4b)(14b-9a)