Question

计算.1.-(x^2y+3xy-4)+3(x^2y-xy+2) 2.-4分之1(2k^3+4k^2-28)+2分之1(k

Answer 1

1.-(x^2y+3xy-4)+3(x^2y-xy+2)

=-x^2y-3xy+4+3x^2y-3xy+6

=+2x^2y-6xy+10

2.-4分之1(2k^3+4k^2-28)+2分之1(k^3-2k^2+4k)

=-2分之1k^3-k^2+7+2分之1k^3-k^2+2k

=-2k^2+2k+7