如果a/b=2则a*a-ab+b*b/a*a+b*b求值

Question

如果a/b=2则a*a-ab+b*b/a*a+b*b求值

Answer 1

a/b=2,a=2b
a*a-ab+b*b/a*a+b*b
=(4b^2-2b^2+b^2)/(4b^2+b^2)
=3b^2/5b^2
=3/5