(1/2x+1/3y)(1/3y-1/2x)+1/2x*(1/2x-1/3y),其中x=4,y=6先化简,再求值

问题描述:

(1/2x+1/3y)(1/3y-1/2x)+1/2x*(1/2x-1/3y),其中x=4,y=6先化简,再求值

(1/2x+1/3y)(1/3y-1/2x)+1/2x*(1/2x-1/3y)
=(1/3y+1/2x)(1/3y-1/2x)+1/2x(1/2x-1/3y)
=(1/3y+1/2x)(1/3y-1/2x)-1/2x(1/3y-1/2x)
=(1/3y-1/2x)(1/3y+1/2x-1/2x)
=1/3y(1/3y-1/2x)
=1/9y^2-1/6xy
=1/9×36-1/6×4×6
=4-4
=0