## Elementary Technical Mathematics

$$-6x^3+4x^2-24x+8.$$
We subtract the $x^3$-terms as follows $$8x^3-14x^3=-6x^3$$ then subtract the $x^2$-terms as follows $$6x^2-2x^2=4x^2$$ then subtract the $x$-terms as follows $$-15x-9x=-24x$$ then subtract the constant terms as follows $$7+1=8$$ Hence, the result is $$-6x^3+4x^2-24x+8.$$