已知-m+2n=2, 求(m-2n)²+6n-3m-3的值?已知-m+2n=2, 求5(m-2n)²+6n-3m-3的值?

已知-m+2n=2, 求(m-2n)²+6n-3m-3的值?已知-m+2n=2, 求5(m-2n)²+6n-3m-3的值?
已知-m+2n=2, 求(m-2n)²+6n-3m-3的值?
已知-m+2n=2, 求5(m-2n)²+6n-3m-3的值?

已知-m+2n=2, 求(m-2n)²+6n-3m-3的值?已知-m+2n=2, 求5(m-2n)²+6n-3m-3的值?
5(m-2n)²+6n-3m-3
=5*(-2)²+3*2-3
=20+6-3
=23

-m+2n=2
m-2n=-2
所以原式=(m-2n)²-3(m-2n)-3
=4+6-3
=7

m-2n=-2
3（2n-m）=6
(m-2n)²+6n-3m-3=4+6-3=7

-m+2n=2 则 -(m-2n)=2 m-2n=-2
(m-2n)²+6n-3m-3=(-2)²-3m+6n-3=4-3(m-2n)-3=4-3*(-2)-3=4+6-3=7

-m+2n=2 --> -2=m-2n
5(m-2n)^2 +6n-3m-2 --> 5(m-2n)^2 +3(2n-m)-2 --> 5(m-2n)^2 -3(m-2n)-2
习题要多做点