Question

已知X+7X-4=0,求(X+2)(X+3)(X+4)(X+5)的值

Answer 1

是不是已知x^2+7x-4=0?

如果是则

x^2+7x=4

(x+2)(x3)(x+4)(x+5)

=[(x+2)(x+5)][(x+3)(x4)]

=(x^2+7x+10)(x^2+7x+12)

=(4+10)*(4+12)

=14*16

=224