$150 per hour is how much per min

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.

How to write four times a number, minus 6,is equal to theee times the number+8 as an equqtion

Find the maximum value of p= 4x + 5y subject to the following constraints :