1.化简求值 a+{b-2a+[3a-2(b+2a)+5b]},其中a=二分之一,b=-12.已知:A=4a²b-5b³,B=-3a²b+2b³ 则2A-B=?3.当x=负二分之一时,代数式(2x²-x-1)-(x²-x-三分之一)+(3x²-三又三分之一
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![1.化简求值 a+{b-2a+[3a-2(b+2a)+5b]},其中a=二分之一,b=-12.已知:A=4a²b-5b³,B=-3a²b+2b³ 则2A-B=?3.当x=负二分之一时,代数式(2x²-x-1)-(x²-x-三分之一)+(3x²-三又三分之一](/uploads/image/z/683875-19-5.jpg?t=1.%E5%8C%96%E7%AE%80%E6%B1%82%E5%80%BC+a%2B%EF%BD%9Bb-2a%2B%5B3a-2%EF%BC%88b%2B2a%EF%BC%89%2B5b%5D%EF%BD%9D%2C%E5%85%B6%E4%B8%ADa%3D%E4%BA%8C%E5%88%86%E4%B9%8B%E4%B8%80%2Cb%3D-12.%E5%B7%B2%E7%9F%A5%EF%BC%9AA%3D4a%26sup2%3Bb-5b%26sup3%3B%2CB%3D-3a%26sup2%3Bb%2B2b%26sup3%3B+%E5%88%992A-B%3D%3F3.%E5%BD%93x%3D%E8%B4%9F%E4%BA%8C%E5%88%86%E4%B9%8B%E4%B8%80%E6%97%B6%2C%E4%BB%A3%E6%95%B0%E5%BC%8F%EF%BC%882x%26sup2%3B-x-1%EF%BC%89-%EF%BC%88x%26sup2%3B-x-%E4%B8%89%E5%88%86%E4%B9%8B%E4%B8%80%EF%BC%89%2B%EF%BC%883x%26sup2%3B-%E4%B8%89%E5%8F%88%E4%B8%89%E5%88%86%E4%B9%8B%E4%B8%80)
1.化简求值 a+{b-2a+[3a-2(b+2a)+5b]},其中a=二分之一,b=-12.已知:A=4a²b-5b³,B=-3a²b+2b³ 则2A-B=?3.当x=负二分之一时,代数式(2x²-x-1)-(x²-x-三分之一)+(3x²-三又三分之一
1.化简求值 a+{b-2a+[3a-2(b+2a)+5b]},其中a=二分之一,b=-1
2.已知:A=4a²b-5b³,B=-3a²b+2b³ 则2A-B=?
3.当x=负二分之一时,代数式(2x²-x-1)-(x²-x-三分之一)+(3x²-三又三分之一)的值是?
4.如果(3x²-y)-(3x²-2y)=2,那么代数式(x+y)+3(x-y)-4(x-y-2)的值是?
1.化简求值 a+{b-2a+[3a-2(b+2a)+5b]},其中a=二分之一,b=-12.已知:A=4a²b-5b³,B=-3a²b+2b³ 则2A-B=?3.当x=负二分之一时,代数式(2x²-x-1)-(x²-x-三分之一)+(3x²-三又三分之一
a+{b-2a+[3a-2(b+2a)+5b]}
=a+{b-2a+[3a-2b-4a+5b]}
=a+{b-2a+3b-a}
=a+4b-3a
=4b-2a
=4(-1)-2*1/2
=-4-1
=-5
2.已知:A=4a²b-5b³,B=-3a²b+2b³
2A-B
=2(4a²b-5b³)-(-3a²b+2b³)
=8a²b-10b³+3a²b-2b³
=11a²b-12b³
=b(11a^2-12b^2)
3.当x=负二分之一时,
(2x²-x-1)-(x²-x-1/3)+(3x²-3又1/3)
=4x^2-4
=4(x^2-1)
=4[(-1/2)^2-1]
=4(1/4-1)
=-3
4.如果(3x²-y)-(3x²-2y)=2=y
(x+y)+3(x-y)-4(x-y-2)
=4x-4x+4y+8
=4y+8
=4*2+8
=16
=a+[b-2a+(-a+3b)]
=a+b-2a-a-3b
=-2*(0.5-1)
=1
11a2b-12b3
(⊙_⊙)?one分钟后 ⊙﹏⊙b汗