Answer:
[tex]\Huge\boxed{x=42}[/tex]
Step-by-step explanation:
Hello There!
The shown angles are supplementary angles.
We know this because a straight line is split into two angles
A straight line creates a 180 degree angle so the sum of the two angles is 180
So we can use this equation to solve for x
180 = 3x + 12 + x
3x + x = 4x
180=4x+12
step 1 subtract 12 from each side
180-12=168
12-12 cancels out
now we have
168=4x
step 2 divide each side by 4
4x/4=x
168/4=42
we're left with x = 42
