\(a,=2x^2-x-4x^2+2x-1=-2x^2+x-1\\ c,=-10x^3-15x^2+25x-5x^3+15x^2-1=-15x^3+25x-1\\ e,=x^4+2x^3+x-25-2x^3-10x=x^4-9x-25\)
a) x(2x-1)-(4x2-2x+1) = 2x2-x-4x2+2x-1 = -2x2+x-1
c) -5x(2x2+3x-1)+(-5x3+15x2-1)
= -10x3-15x2+5x-5x3+15x2-1
= -15x3+5x-1
e) (x4+2x3+x-25)-2x(x2+5)
= x4+2x3+x-25-2x3-10x
= x4-9x-25


