a) Diagonals of a square bisect so SR = 2 * ST = 4x + 6
Diagonals of a square are equal so SR = EQ:
4x + 6 = 6x - 11
2x = 17
x = 8.5
EQ = 6(8.5) - 11 = 40
b)
In a square diagonals are perpendicular so m<ETS = 90
Also all four interior angles are right angles so m<ERQ = 90
so 3w -z = 90
w - 2z = 90
multiply top row by -2
-6w + 2z = -180
w - 2z = 90
add two rows
-5w = -90
w = 18
w - 2z = 90
18 -2z = 90
-2z = 72
z = -36