What is the answer for -11x-11

If a and b are the measures of two first quadrant angles and sin a = 4/9 and sin b = 2/5 find sin(a+b).

You paid 28.00 for 8 gallons of gasoline. how much would you pay for 15 gallons of gasoline?

The rectangle shown has a perimeter of 108 cm and the given area. its length is 6 more than five times its width. write and solve a system of equations to find the dimensions of the rectangle.