15 points if you solve

2x + 3y = 9 -2x + 2y = 6 the y-coordinate of the solution to the system shown is

3
5
9
15

△cde maps to △stu with the transformations (x, y) arrowright (x − 2, y − 2) arrowright (3x, 3y) arrowright (x, −y). if cd = a + 1, de = 2a − 1, st = 2b + 3 and tu = b + 6, find the values of a and b. the value of a is and the value of b is .

The solution set for 5v2 – 125 = 0 is

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?