Question

已知长方形的周长为300cm,两边长为x和y,且x³+x²y—4xy²—4y³=

Answer 1

5000cm2

x3+x2y-4xy2-4y3=0 x2(x+y)-4y2(x+y)=0

(x+2y)(x+y)(x-2y)=0 x=2y x+y=150 x=100 y=50 xy=5000