已知(2x-y)/(x+3y)=2,求代数式(4x-2y)/(x+3y) -(4x+12y)/(2x-y)
∵(2x-y)/(x+3y)=2
∴(x+3y)/(2x-y)=1/2
∴(4x-2y)/(x+3y) -(4x+12y)/(2x-y)
=2*(2x-y)/(x+3y)-4*(x+3y)/(2x-y)
=2*2-4*(1/2)
=2
已知2a+b=4,求代数式(2a+b)²- 12/4a+2b
1/(2a+b)=1/4
(2a+b)²- 12/4a+2b
=(2a+b)²-12/2(2a+b)
=16-3/2
=29/2/是分数线