You have the square QRST, furthermore, you have that sides QS and QU are given by the following algebraic expressions:
QS = 16t - 14
QU = 6t + 11
Due to QRST is a square, the length of all sides are equal.
You can notice by the symmetry of the figure that QS = 2QU
Equal the expressions for QS and 2QU and solvde for t:
16t - 14 = 2(6t + 11) apply distribution property
16t - 14 = 12t + 22 add 14 both sides
16t = 12t + 22 + 14 subtract 12t both sides
16t - 12t = 22 + 14 simplfy like terms
4t = 36 divide by 4 both sides
t = 36/4 simplify the fraction
t = 9
Hence, the value of t is t = 9