30 because you add 8 and 7 then add it by itself or multiply it by 2
X/6.2=-2.1
multiply both sides by 6.2
x=-13.02
The figure is shown below
From the figure
Angle 150 degree and angle p forms angles on a straight
Since the sum of angles on a straight line equals 180 degrees
Hence

Solve for p in the equation

Hence, p = 30
From the figure
Angle p and angle q are vertically opposite angles
Since vertically opposite angles are equal then

Hence, q = 30
Applying the rule of angles on a straight line
This implies

Substitute q = 30 into the equation

Solve for w

Hence, w = 90
4x-8 = 31
4x = 31 + 8
4x = 39
x = 9.75