First question refers to the supplementary angle theorem.
To find x, we need to refer to the other angles around it and use it to subtract it from 180°.
90 + 45 + x = 180
135 + x = 180
x = 180 - 135
x = 45°
Second question refers to the vertical angles theorem, where it states that the angles that face in opposite directions are the same.
7x = 112
x = 112 ÷ 7
x = 16°
