1.已知M=a²-4ab+4b²,N=-5a²+ab+b².求:(1)2M-3N;(2)3M+2N.2.已知丨x-1丨+(y-1)²=0.求代数式(x²+4xy-2y²)-(x²+y)-2(y²+xy)-2/1(x-8y²)2/1是二分之一。忘记补充了。
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![1.已知M=a²-4ab+4b²,N=-5a²+ab+b².求:(1)2M-3N;(2)3M+2N.2.已知丨x-1丨+(y-1)²=0.求代数式(x²+4xy-2y²)-(x²+y)-2(y²+xy)-2/1(x-8y²)2/1是二分之一。忘记补充了。](/uploads/image/z/3996080-8-0.jpg?t=1.%E5%B7%B2%E7%9F%A5M%3Da%26sup2%3B-4ab%2B4b%26sup2%3B%2CN%3D-5a%26sup2%3B%2Bab%2Bb%26sup2%3B.%E6%B1%82%3A%281%292M-3N%EF%BC%9B%282%293M%2B2N.2.%E5%B7%B2%E7%9F%A5%E4%B8%A8x-1%E4%B8%A8%2B%28y-1%29%26sup2%3B%3D0.%E6%B1%82%E4%BB%A3%E6%95%B0%E5%BC%8F%28x%26sup2%3B%2B4xy-2y%26sup2%3B%29-%28x%26sup2%3B%2By%29-2%28y%26sup2%3B%2Bxy%29-2%2F1%28x-8y%26sup2%3B%292%2F1%E6%98%AF%E4%BA%8C%E5%88%86%E4%B9%8B%E4%B8%80%E3%80%82%E5%BF%98%E8%AE%B0%E8%A1%A5%E5%85%85%E4%BA%86%E3%80%82)
1.已知M=a²-4ab+4b²,N=-5a²+ab+b².求:(1)2M-3N;(2)3M+2N.2.已知丨x-1丨+(y-1)²=0.求代数式(x²+4xy-2y²)-(x²+y)-2(y²+xy)-2/1(x-8y²)2/1是二分之一。忘记补充了。
1.已知M=a²-4ab+4b²,N=-5a²+ab+b².求:(1)2M-3N;(2)3M+2N.
2.已知丨x-1丨+(y-1)²=0.
求代数式(x²+4xy-2y²)-(x²+y)-2(y²+xy)-2/1(x-8y²)
2/1是二分之一。忘记补充了。
1.已知M=a²-4ab+4b²,N=-5a²+ab+b².求:(1)2M-3N;(2)3M+2N.2.已知丨x-1丨+(y-1)²=0.求代数式(x²+4xy-2y²)-(x²+y)-2(y²+xy)-2/1(x-8y²)2/1是二分之一。忘记补充了。
2M-3N=2(a2-4ab+4b2)-3(-5a2+ab+b2)=17a2-10ab+5b2
3M+2N=3(a2-4ab+4b2)+2(-5a2+ab+b2)=-7a2-10ab+14b2
由丨x-1丨+(y-1)2=0,可得x=1,y=1
带入(x2+4xy-2y2)-(x2+y)-2(y2+xy)-2/1(x-8y2)计算就行了
=3-2-4-1/2*(-7)=1/2
第一题:2M-3N=17a²-11ab+5b²:;3M+2N=-7a²-10ab+14b²
第二题:x=1,y=1,往下有错误吧,你几年级啊?
因为 丨x-1丨+(y-1)²=0.
丨x-1丨>=0
(y-1)²>=0
两式相加等于0,所以丨x-1丨=0
(y-1)²=0
所以 x=1
y=1
(x²+4xy-2y²)-(x²+y)-2(y²+xy)-2/1(x-8y²)
=(x-2y)²-(1+1)-2(1+1)-1/2(1-8)=1-2-4+3.5=-0.5
1.已知M=a²-4ab+4b²,N=-5a²+ab+b². 求:(1)2M-3N;(2)3M+2N。
2M-3N=17a²-11ab+5b²
3M+2N=-7a²-10ab+14b²
2.已知丨x-1丨+(y-1)²=0
求代数式(x²+4xy-2y&su...
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1.已知M=a²-4ab+4b²,N=-5a²+ab+b². 求:(1)2M-3N;(2)3M+2N。
2M-3N=17a²-11ab+5b²
3M+2N=-7a²-10ab+14b²
2.已知丨x-1丨+(y-1)²=0
求代数式(x²+4xy-2y²)-(x²+y)-2(y²+xy)-2/1(x-8y²)
(x²+4xy-2y²)-(x²+y)-2(y²+xy)-2/1(x-8y²)=0.5
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