1.(2a-b+3)(2a-3+b)2.20012001*4002-40024002*20013.(a-b)x的平方+(a-b)xy-1/4(b-a)y 的平方4.(x的平方-2x)的平方+2(x平方-2x)+15.a的8次方-1/2566.先化简,在求值2(x-y)的平方-(y-x的平方)-(x+y)
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1.(2a-b+3)(2a-3+b)2.20012001*4002-40024002*20013.(a-b)x的平方+(a-b)xy-1/4(b-a)y 的平方4.(x的平方-2x)的平方+2(x平方-2x)+15.a的8次方-1/2566.先化简,在求值2(x-y)的平方-(y-x的平方)-(x+y)
1.(2a-b+3)(2a-3+b)
2.20012001*4002-40024002*2001
3.(a-b)x的平方+(a-b)xy-1/4(b-a)y 的平方
4.(x的平方-2x)的平方+2(x平方-2x)+1
5.a的8次方-1/256
6.先化简,在求值
2(x-y)的平方-(y-x的平方)-(x+y)(y-x),求种x=3,y=-2
错误率不要太高
1.(2a-b+3)(2a-3+b)2.20012001*4002-40024002*20013.(a-b)x的平方+(a-b)xy-1/4(b-a)y 的平方4.(x的平方-2x)的平方+2(x平方-2x)+15.a的8次方-1/2566.先化简,在求值2(x-y)的平方-(y-x的平方)-(x+y)
1.
(2a-b+3)(2a-3+b)
=[2a-(b-3)][2a+(b-3)]
=4a²-(b-3)²
=4a²-b²+6b-9
2.
20012001*4002-40024002*2001
=20012001*2001*2-2*20012001*2001
=0
3.
(a-b)x²+(a-b)xy-1/4(b-a)y ²
=(a-b)x²+(a-b)xy+1/4(a-b)y ²
=(a-b)(x²+xy+y²/4)
=(a-b)(x+y/2)²
4.(x²-2x)²+2(x²-2x)+1
=[(x²-2x)+1]²
=(x²-2x+1)²
=(x-1)^4
5.
a^8-1/256
=(a^4+1/16)(a^4-1/16)
=(a^4+1/16)(a²+1/4)(a²-1/4)
=(a^4+1/16)(a²+1/4)(a+1/2)(a-1/2)
6.先化简,在求值x=3,y=-2
2(x-y)²-(y²-x²)-(x+y)(y-x)
=2(x-y)²-(y-x)(x+y)-(x+y)(y-x)
=2(x-y)²+2(x+y)(x-y)
=2(x-y)(x-y+x+y)
=4x(x-y)
=12*5
=60
1.(2a-b+3)(2a-3+b)
={2a-(b-3)}{2a+(b-3)}
=4a^2-(b-3)^2
=4a^2-b^2+6b-9
2.20012001*4002-40024002*2001
=20012001*(4002-2*2001)
=0
3.(a-b)x^2+(a-b)xy-1/4(b-a)y ^2
=(a-b)(x^...
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1.(2a-b+3)(2a-3+b)
={2a-(b-3)}{2a+(b-3)}
=4a^2-(b-3)^2
=4a^2-b^2+6b-9
2.20012001*4002-40024002*2001
=20012001*(4002-2*2001)
=0
3.(a-b)x^2+(a-b)xy-1/4(b-a)y ^2
=(a-b)(x^2+xy+1/4y^2)
=(a-b)(x+y/2)^2
4.(x^2-2x)^2+2(x^2-2x)+1
={(x^2-2x)+1}^2
=(x-1)^4
5.a^8-1/256
=a^8-(1/2)^8
={a^4+(1/2)^4}{a^4-(1/2)^4}
={a^4+(1/2)^4}{a^2+(1/2)^2}{a^2-(1/2)^2}
={a^4+(1/2)^4}{a^2+(1/2)^2}{a+1/2}{a-1/2}
6.先化简,在求值
2(x-y)^2-(y-x^2)-(x+y)(y-x)
2x^2-4xy+2y^2-y+x^2-y^2+x^2
=4x^2-4xy+y^2-y,x=3,y=-2
=36+24+4+2
=66
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1.(2a-b+3)(2a-3+b)=[2a-(b-3)][2a+(b-3)]=2a^2-b^2+9 (这是整式的乘法吧!)
2.20012001*4002-40024002*2001=20012001*2001*2-20012001*2*2001=0
3.(a-b)x的平方+(a-b)xy-1/4(b-a)y 的平方=.a-b)x^2+(a-b)xy+1/4(a-b)y ^2...
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1.(2a-b+3)(2a-3+b)=[2a-(b-3)][2a+(b-3)]=2a^2-b^2+9 (这是整式的乘法吧!)
2.20012001*4002-40024002*2001=20012001*2001*2-20012001*2*2001=0
3.(a-b)x的平方+(a-b)xy-1/4(b-a)y 的平方=.a-b)x^2+(a-b)xy+1/4(a-b)y ^2=(a-b)(x^2+xy+1/4)=(a-b)(x+1/2)^2
4.(x的平方-2x)的平方+2(x平方-2x)+1=(x^2-2x+1)^2=[(x-1)^2]^2=(x-1)^4
5.a的8次方-1/256=(a^4)^2-(1/16)^2=(a^4+1/16)[a^4-(1/4)^2]=(a^4+1/16)(a^2+1/4)(a^2-1/4)=(a^4+1/16)(a^2+1/4)(a+1/2)(a-1/2)
6.先化简,在求值
2(x-y)的平方-(y-x的平方)-(x+y)(y-x),求种x=3,y=-2(题目有问题吧)
化简:原式=2(x²-2xy+y²)-(y-x²)-(y²-x²)
=4x²-4xy+y²-y
=(2x-y)²-y
=(6+2)²+2
=66
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(1)原式=[2a+(3-b)][2a-(3-b)]=(2a)²-(3-b)²=4a²-(9-6b+b²)=4a²-b²+6b-9.(2) 原式=(20012001×2)×2001-40024002×2001=40024002×2001-40024002×2001=0,(3)原式=(a-b)(x+½y)²(4)原式...
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(1)原式=[2a+(3-b)][2a-(3-b)]=(2a)²-(3-b)²=4a²-(9-6b+b²)=4a²-b²+6b-9.(2) 原式=(20012001×2)×2001-40024002×2001=40024002×2001-40024002×2001=0,(3)原式=(a-b)(x+½y)²(4)原式=(x²-2x+1)²=(x-1)^4 (5)原式=(a^4)²-(1/16)²=(a^4+1/16)(a²+1/4)(a+1/2)(a-1/2) 2,化简得3x²-2xy-y.值为41.
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