Subtract 4x^3-6x^2+8x-9 from 7x^3-16+18

To evaluate the expression we proceed as follows;

(7x³-16x+8) - (4x³-6x²+8x-9)

opening the parenthesis we have:

7x³+0x²-16x+8-4x³+6x²-8x+9

putting like terms together we get:

(7x³-4x³) + (-16x-8x) + (8+9) + (0x²+6x²)

=3x³+6x²-24x+17

the answer is

=3x³+6x²-24x+17