Question

几道数学题求解呀 速度呀 大侠们

化简：(5/3 a^2 b-10/3 a^3 b^2 +1)(-0.2ab) 已知x=1/2,求x^2(x^2-x+1)-x(x^3-x^2+x-1)的值 已知2x·(x^n + 2)=2x^n+1 - 4,求x的值

Answer 1

1、(5/3 a^2 b-10/3 a^3 b^2 +1)(-0.2ab)
=(5/3*(-1/5) a^2 b *ab-10/3*(-1/5)a^3 b^2*ab -1/5ab)
= (-1/3)a^3 b^2 + 2/3 a^4 b^3 -1/5ab
=2/3a^4 b^3-1/3a^3 b^2-1/5ab
=ab(2/3 a^3 b^2 -1/3 a^2b -1/5)

2、x^2(x^2-x+1)-x(x^3-x^2+x-1)
=x^4-x^3+x^2-x^4+x^3-x^2+x
=x
=1/2
3、2x·(x^n + 2)=2x^(n+1) - 4
2x^(n+1)+4x=2x^(n+1)-4
4x=-4
x=-1

Answer 2

化简：(5/3 a^2 b-10/3 a^3 b^2 +1)(-0.2ab)
= (5/3*(-1/5) a^2 b *ab -10/3 *(-1/5) a^3 b^2 *ab -0.2ab)
= (-1/3) *a^3 b^2 + 2/3 * a^4 b^3 -0.2ab
=2/3 * a^4 b^3 - 1/3 *a^3 b^2 - -0.2ab
=ab(2/3 a^3 b^2 -1/3 a^2b -0.2)

已知x=1/2,求x^2(x^2-x+1)-x(x^3-x^2+x-1)的值
==== x^4-x^3+x^2-x^4+x^3-x^2+x

=== x =1/2 什么垃圾题目啊

已知2x·(x^n + 2)=2x^(n+1) - 4,求x的值 漏掉括号 你真郁闷啊
2x*（x^n+2）=2x^( n+1)-4
2x^(n+1)+4x=2x^(n+1)-4
4x=-4
x=-1

Answer 3

吧鐧惧害鍦板浘

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