Assume all items are Lipgloss Total Cost -> $7 x 9 = $63 difference-> $63-$50.50= $12.50 Assume that all were Lipgloss except for one item Total Cost-> ($7x8)+$4.50= $60.50 diff-> $63-$60.50=$2.50 Number of Nail Polishes-> $12.50 diveded by $2.50 = 5 Number of Lipglosses-> 9-5=4 ANSWER: Lipglosses:4 Nail Polishes :5
F ( x ) = 7 x + 2 y = 7 x + 2 - 7 x = - y + 2 /*(-1) 7 x = y - 2 / : 7 x = y/7 - 2/7 = ( y - 2 ) / 7 The inverse of the function is: f^(-1) ( x ) = ( x - 2 ) /7