1.
f(x)=x3-x
g(x)=x3+2x2-10
So (f+g)(x) = ?
2.
f(x)=x2+2x-6
g(x)=x4+3
So (f*g)(x) = ?
3.
f(x)=x4-x2+9
g(x)=x3+3x2+12
So (f-g)(x) = ?
1) (f + g)(x) = (x3 - x) + (x3 + 2x2 - 10) = (x3 + x3) + 2x2 - x - 10 = 2x3 + 2x2 - x - 10
2) (f * g)(x) = (x2 + 2x - 6)(x4 + 3) = x6 + 2x5 - 6x4 + 3x2 + 6x -18) [distributive property]
3) (f - g)(x) = (x4 - x2 + 9) - (x3 + 3x2 + 12) = x4 - x2 + 9 - x3 - 3x2 - 12 = x4 - x3 - 4x2 - 3