a) f(x)-g(x)+h(x)
= (x³-2x²+3x+1)-(x³+x-1)+(2x²-1)
= x³-2x²+3x+1-x³-x+1+2x²-1
= (x³-x³)+(2x²-2x²)+(3x-x)+(1+1-1)
= 2x+1
b) f(x)-g(x)+h(x)= 0 ⇒ 2x+1=0 ⇒ x=-1/2
c) A(x)=2f(x)+g(x)
=2(x³-2x²+3x+1)+(x³+x-1)
=(2x³-4x²+6x+2)+(x³+x-1)
=2x³-4x²+6x+2+x³+x-1
=(2x³+x³)-4x²+(6x+x)+(2-1)
=3x³-4x²+7x+1
d) 2B(x)+f(x) =h(x)
⇒ 2B(x)=h(x)-f(x)
=(2x²-1)-(x³-2x²+3x+1)
=2x²-1-x³+2x²-3x-1
=-x³+(2x²+2x²)-3x+(-1-1)
=-x³+4x²-3x-2
⇒ B(x)=(-x³+4x²-3x-2)÷2=-0,5x³+2x²-1,5x-1
e) C(x)=2g(x)-3h(x)
=2(x³+x-1)-3(2x²-1)
=(2x³+2x-2)-(6x²-3)
=2x³+2x-2-6x²+3
=2x³-6x²+2x+(3-2)
=2x³-6x²+2x+1