Step-by-step explanation
Step 1
Vertical angles are formed when two lines intersect each other. Out of the 4 angles that are formed, the angles that are opposite to each other are vertical angles. vertical angles are congruent so

Step 1
replace the given values

now, we need to solve for x
a)

b)subtract 3x in both sides( additioin or subtraction property of equality)

c) finally, divide both sides by (-9) division property of equality

i hope this helps you