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?
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/21 10:03:45
![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?](/uploads/image/z/2586364-52-4.jpg?t=%E5%B7%B2%E7%9F%A5-m%2B2n%3D2%2C+%E6%B1%82%28m-2n%29%26%23178%3B%2B6n-3m-3%E7%9A%84%E5%80%BC%3F%E5%B7%B2%E7%9F%A5-m%2B2n%3D2%2C+%E6%B1%825%28m-2n%29%26%23178%3B%2B6n-3m-3%E7%9A%84%E5%80%BC%3F)
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