12+18n+7-14n write an equivalent expression using like terms

When the ball has traveled a distance of

Satchi found a used bookstore that sells pre-owned dvds and cds. dvds cost $9 each, and cds cost $7 each. satchi can spend no more than $45.

Use composition to determine if (x) or h(x) is the inverse of f(x) for the limited domain x2-1.