Mary went to a computer store and saw a computer priced for $400. She had a coupon for 15% off. After applying the coupon she had to pay 6% tax. How much did she pay for the computer?

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.