(1)若m²+2mn+2n²-6n+9=0求m/n²的值(2)已知:4m+n=90,2m-3n=10,求(m+2n)²-(3m-n)²的值
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![(1)若m²+2mn+2n²-6n+9=0求m/n²的值(2)已知:4m+n=90,2m-3n=10,求(m+2n)²-(3m-n)²的值](/uploads/image/z/5032563-51-3.jpg?t=%281%29%E8%8B%A5m%26%23178%3B%2B2mn%2B2n%26%23178%3B-6n%2B9%3D0%E6%B1%82m%2Fn%26%23178%3B%E7%9A%84%E5%80%BC%282%29%E5%B7%B2%E7%9F%A5%EF%BC%9A4m%2Bn%3D90%2C2m-3n%3D10%2C%E6%B1%82%EF%BC%88m%2B2n%EF%BC%89%26%23178%3B-%EF%BC%883m-n%EF%BC%89%26%23178%3B%E7%9A%84%E5%80%BC)
(1)若m²+2mn+2n²-6n+9=0求m/n²的值(2)已知:4m+n=90,2m-3n=10,求(m+2n)²-(3m-n)²的值
(1)若m²+2mn+2n²-6n+9=0求m/n²的值
(2)已知:4m+n=90,2m-3n=10,求(m+2n)²-(3m-n)²的值
(1)若m²+2mn+2n²-6n+9=0求m/n²的值(2)已知:4m+n=90,2m-3n=10,求(m+2n)²-(3m-n)²的值
(1)m²+2mn+2n²-6n+9=0
m²+2mn+n²+n²-6n+9=0
(m+n)²+(n-3)²=0
所以m+n=0,n-3=0
所以n=3.m=-3
所以m/n²=-3/9=-1/3
2)(m+2n)²-(3m-n)²
=(m+2n+3m-n)(m+2n-3m+n)
=(4m+n)(-2m+3n)
=-(4m+n)(2m-3n)
=-90*10
=-900