x = 21 and angle QXS = 40°
angle QXT = angle QXS + angle SXT
that is 2x - 2 + 4x + 1 = 125
6x - 1 = 125
add 1 to both sides
6x = 125 + 1 = 126
divide both sides by 6
x = [tex]\frac{126}{6}[/tex] = 21
angle QXS = 2x - 2 = (2 × 21) - 2 = 42 - 2 = 40°
