Question

已知/a-4/+√(b-9)=0,计算（a²+ab）/(b²)·（a²-ab）/(a

Answer 1

因为|a-4|+√(b-9)=0,|a-4|≥0,√(b-9)≥0

所以a-4=0且b-9=0

a=4,b=9

所以

(a²+ab)/(b²)×(a²-ab)/(a²-b²)

=[a(a+b)]/(b²)×[a(a-b)]/[(a+b)(a-b)]

=(a²)/(b²)

=(4²)/(9²)

=16/81