一.计算：1.（m^2-3m+2）-(4m-2n-1) 2.(3x^2+4x-1)-3(x^2+3x) 3.-5(x^2-3)-2(3x^2+5)

题目

一.计算：1.（m^2-3m+2）-(4m-2n-1) 2.(3x^2+4x-1)-3(x^2+3x) 3.-5(x^2-3)-2(3x^2+5)
4.-(x^2y+3xy-4)+3(x^2y-xy+2) 5.(11/2x^2-29x+10y)-(5/2x^2-13x+24y) 6.-1/4(2k^3+4k^2-28)+1/2(k^3-2k^2+4k) 一步都不能少!

答案

一.计算：
1.（m^2-3m+2）-(4m-2n-1)
=m^2-3m+2-4m+2n+1
=m^2-7m+2n+3
2.(3x^2+4x-1)-3(x^2+3x)
=3x^2+4x-1-3x^2-9x
=-5x-1
3.-5(x^2-3)-2(3x^2+5)
=-5x^2+15-6x^2-10
=-11x^2+5
4.-(x^2y+3xy-4)+3(x^2y-xy+2)
=-x^2-3xy+4+3x^2y-3xy+6
=-x^2-6xy+3x^2y+10
5.(11/2x^2-29x+10y)-(5/2x^2-13x+24y)
=11/2x^2-29x+10y-5/2x^2+13x-24y
=3x^2-16x-14y
6.-1/4(2k^3+4k^2-28)+1/2(k^3-2k^2+4k)
=-1/2*k^3-k^2+7+1/2*k^3-k^2+2k
=-2k^2+2k+7