已知m,x,y满足条件:(1)2/3(x-5)²+5×(m的绝对值)=0;(2)-2a²b^(y+1)与7b³a²是同类项.求代数式2x²-6y²+m(xy-9y²)-(3x²-3xy+7y²)的值.
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![已知m,x,y满足条件:(1)2/3(x-5)²+5×(m的绝对值)=0;(2)-2a²b^(y+1)与7b³a²是同类项.求代数式2x²-6y²+m(xy-9y²)-(3x²-3xy+7y²)的值.](/uploads/image/z/1265914-10-4.jpg?t=%E5%B7%B2%E7%9F%A5m%2Cx%2Cy%E6%BB%A1%E8%B6%B3%E6%9D%A1%E4%BB%B6%EF%BC%9A%EF%BC%881%EF%BC%892%2F3%28x-5%29%26%23178%3B%2B5%C3%97%28m%E7%9A%84%E7%BB%9D%E5%AF%B9%E5%80%BC%EF%BC%89%3D0%EF%BC%9B%EF%BC%882%EF%BC%89-2a%26%23178%3Bb%5E%28y%2B1%29%E4%B8%8E7b%26%23179%3Ba%26%23178%3B%E6%98%AF%E5%90%8C%E7%B1%BB%E9%A1%B9.%E6%B1%82%E4%BB%A3%E6%95%B0%E5%BC%8F2x%26%23178%3B-6y%26%23178%3B%2Bm%EF%BC%88xy-9y%26%23178%3B%EF%BC%89-%EF%BC%883x%26%23178%3B-3xy%2B7y%26%23178%3B%EF%BC%89%E7%9A%84%E5%80%BC.)
已知m,x,y满足条件:(1)2/3(x-5)²+5×(m的绝对值)=0;(2)-2a²b^(y+1)与7b³a²是同类项.求代数式2x²-6y²+m(xy-9y²)-(3x²-3xy+7y²)的值.
已知m,x,y满足条件:(1)2/3(x-5)²+5×(m的绝对值)=0;(2)-2a²b^(y+1)与7b³a²是同类项.求代数式2x²-6y²+m(xy-9y²)-(3x²-3xy+7y²)的值.
已知m,x,y满足条件:(1)2/3(x-5)²+5×(m的绝对值)=0;(2)-2a²b^(y+1)与7b³a²是同类项.求代数式2x²-6y²+m(xy-9y²)-(3x²-3xy+7y²)的值.
由2/3(x-5)²+5×(m的绝对值)=0可知,M=0,x=5,由)-2a²b^(y+1)与7b³a²是同类项可知y+1=3,y=2,所以2x²-6y²+m(xy-9y²)-(3x²-3xy+7y²)=2×5^2-6×2^2+0-3×5^2+3×5×2-7×2^2=-47
已知m,x,y满足条件:(1)2/3(x-5)²+5×(m的绝对值)=0;非负数加非负数的和为0,则两个式子分别为0。所以x=5,m=0。(2)-2a²b^(y+1)与7b³a²是同类项。y+1=3,y=2。求代数式2x²-6y²+m(xy-9y²)-(3x²-3xy+7y²)的值。代数式2x²-6...
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已知m,x,y满足条件:(1)2/3(x-5)²+5×(m的绝对值)=0;非负数加非负数的和为0,则两个式子分别为0。所以x=5,m=0。(2)-2a²b^(y+1)与7b³a²是同类项。y+1=3,y=2。求代数式2x²-6y²+m(xy-9y²)-(3x²-3xy+7y²)的值。代数式2x²-6y²+m(xy-9y²)-(3x²-3xy+7y²)化简为:-x²-13y²-9my²+3xy+mxy =-x²-(13+9m)y²+(3+m)xy把x=5,m=0,y=2,代入-x²-(13+9m)y²+(3+m)xy=-25-52+30=-47
问题补充:
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(1)x-5=0 m=0
(2)y+1=3
x=5 m=0 y=2 代入得-47