How do you put -10(4x-5) into a equeation like 40x-50

Solve the system of equations using the substitution method. {y=−3x+7x=−2y−16 enter your answers in the boxes.

Perform the indicated operation. y^2 + 3y - 10 / 3y + 15

If using the method of completing the square to solve the quadratic equation x 2 + 16 x + 24 = 0 x 2 +16x+24=0, which number would have to be added to "complete the square"?