Ihave a question about i need to use substitution to solve the system of equations x + y = 12 & x - y = 2. pls show work..

Celeste wants to have her hair cut and permed and also go to lunch. she knows she will need $50. the perm cost twice as much as her haircut and she needs $5 for lunch. how much does the perm cost?

The perimeter of a rectangle is 42 inches. if the width of the rectangle is 6 inches, what is the length

What is the maximum of the sinusoidal function