Answer:
x = 3
Step-by-step explanation:
The external angle of a triangle is equal to the sum of the 2 opposite interior angles
∠ QRT is an external angle, thus
∠ QRT = ∠ RTS + ∠ RST, substitute values
45x = 25x + 57 + x
45x = 26x + 57 ( subtract 26x from both sides )
19x = 57 ( divide both sides by 19 )
x = 3
