1.25^a•5^b的计算结果是（ ）A.5^a+b B.5^2a+b C.5^a+2b 25^a+b2.若-x^2*y=2,则-xy(x^5*y^2-x^3*y+2x)的值为（ ）A.16 B.0 C.8 D.12计算1.2a(a^2 +3a-2)-3(a^3 + 2a^2 -a+1)2.(a^2 +3)(a-2)-a(a^2 -2a-2)化简求值1． X^2(x^2 -x+1)-x(x^3 -

1.25^a•5^b的计算结果是（ ）A.5^a+b B.5^2a+b C.5^a+2b 25^a+b2.若-x^2*y=2,则-xy(x^5*y^2-x^3*y+2x)的值为（ ）A.16 B.0 C.8 D.12计算1.2a(a^2 +3a-2)-3(a^3 + 2a^2 -a+1)2.(a^2 +3)(a-2)-a(a^2 -2a-2)化简求值1． X^2(x^2 -x+1)-x(x^3 -
1.25^a•5^b的计算结果是（ ）
A.5^a+b B.5^2a+b C.5^a+2b 25^a+b
2.若-x^2*y=2,则-xy(x^5*y^2-x^3*y+2x)的值为（ ）
A.16 B.0 C.8 D.12
计算
1.2a(a^2 +3a-2)-3(a^3 + 2a^2 -a+1)
2.(a^2 +3)(a-2)-a(a^2 -2a-2)
化简求值
1． X^2(x^2 -x+1)-x(x^3 -x^2 +x-2),其中x=1/4
2.-1/2x^2•(2xy^2 -4x^2y^2)-4x^2y•(-xy),其中x=2,y=-1.

1.25^a•5^b的计算结果是（ ）A.5^a+b B.5^2a+b C.5^a+2b 25^a+b2.若-x^2*y=2,则-xy(x^5*y^2-x^3*y+2x)的值为（ ）A.16 B.0 C.8 D.12计算1.2a(a^2 +3a-2)-3(a^3 + 2a^2 -a+1)2.(a^2 +3)(a-2)-a(a^2 -2a-2)化简求值1． X^2(x^2 -x+1)-x(x^3 -
B
A
-a^3-a-3
5a-6
1/2
56
够意思吧?!

1 :B
2 : 若-x^2*y=2,则-xy(x^5*y^2-x^3*y+2x)
-x^2y(x^4*y^2-x^2*y+2)
=2[(-x^2y)^2+4]=16 A
1. 2a(a^2 +3a-2)-3(a^3 + 2a^2 -a+1)
=2a^3+6a^2-4a-3a^3-6a^2+3a-3
=-a^3-a-3
2.(a^2...

全部展开

1 :B
2 : 若-x^2*y=2,则-xy(x^5*y^2-x^3*y+2x)
-x^2y(x^4*y^2-x^2*y+2)
=2[(-x^2y)^2+4]=16 A
1. 2a(a^2 +3a-2)-3(a^3 + 2a^2 -a+1)
=2a^3+6a^2-4a-3a^3-6a^2+3a-3
=-a^3-a-3
2.(a^2 +3)(a-2)-a(a^2 -2a-2)
=a^3+3a-2a^2-6-a^3+2a^2+2a=5a-6
化简求值
1． X^2(x^2 -x+1)-x(x^3 -x^2 +x-2),其中x=1/4
x(x^3-x^2+x-x^3+x^2-x+2)
=x(2-x)=1/4(2-1/4)=7/16
2. -1/2x^2•(2xy^2 -4x^2y^2)-4x^2y•(-xy),其中x=2,y=-1.
-1/2x^2•(2xy^2 -4x^2y^2)-4x^2y•(-xy)
=-x^3y^2+2x^4y^2+4x^3y^2
=3x^3y^2+2x^4y^2
=24+16=40
=5a-6

收起

1、B 2.A
计算
1。-a^3-a-3
2.5a-6
化简求值
1.2x其中x=1/4时 原式=1/2
2、-y^2/x+2y^2+4x^3y^2其中x=2,y=-1时 原式=-30.5