(2xy-3)(2xy+3)+(xy+3)^2化简求值 x=1/5 y=-2

问题描述:

(2xy-3)(2xy+3)+(xy+3)^2化简求值 x=1/5 y=-2

x=1/5 , y=-2
xy=-2/5

(2xy-3)(2xy+3)+(xy+3)^2
=(2xy)²-9+(xy)²+6xy+9
=5(xy)²+6xy
=xy(5xy+6)
=(-2/5)[5(-2/5)+6]
=(-2/5)[-2+6]
=(-2/5)[4]
=-8/5