Question

化简代数式的几道题3(x-1)-(x-5)2(x^2-y^2)-3(x^2-2y^2)(x+y)+3(x-y)-4(x+

Answer 1

解

3(x-1)-(x-5)

=3x-3-x+5

=(3x-x)+(5-3)

=2x+2

2(x²-y²)-3(x²-2y²)

=(2x²-3x²)+(-2y²+6y²)

=4y²-x²

(x+y)+3(x-y)-4(x+y-2)

=(x+3x-4x)+(y-3y-4y)+8

=-6y+8

(2x^2-1+3x)-4(x-x^2+1)

=(2x²+4x²)+(3x-4x)+(-1-4)

=6x²-x-5

-3a^2+(3a-5a^2)-1/2(4a^2+6a)

=(-3a²-5a²-2a²)+(3a-3a)

=-10a²

(8mn-3m^2)-5mn-2(3mn-2m^2)

=(8mn-5mn-6mn)+(-3m²+4m²)

=-3mn+m²

3(2x^2-y^2)-2(3y^2-2x^2)

=(6x²+4x²)+(-6y²-3y²)

=10x²-9y²

(8x^3-3x^2+3)-(9x^3-4x^2+5)

=(8x³-9x³)+(-3x²+4x²)+(3-5)

=-x³+x²-2

-(-4ab+b^2)-2(2ab-b^2)

=4ab-b²-4ab+2b²

=b²