Question

(2a-3b)(3a-4b)=0,求a^2-2ab/(a+b)(a-2b)的值

Answer 1

(2a-3b)(3a-4b)=0

2a-3b=0 a=3b/2

3a-4b=0 a=4b/3

a²-2ab/(a+b)(a-2b)

=a(a-2b)/(a+b)(a-2b)

=a/(a+b)

(1)当 a=3b/2

原式=(3b/2)/(3b/2+b)

=(3b/2)/(5b/2)

=3/5

(2)当a=4b/3

原式=(4b/3)/(4b/3+b)

=(4b/3)/(7b/3)

=4/7