Answer: x = 40
Explanation:
these two angles are vertical angles, they will equal each other
therefore, move numbers and variables to the opposite sides of the = sign to isolate the X
3x-10 = 2x + 30
+10 +10 move the -10 by doing opposite
_____________
3x = 2x + 40
-2x -2x move -2x by doing opposite
____________
x = 40
you can check your work by substituting 40 in place of x
3(40) - 10 = 2(40) +30
120-10 = 80 + 30
110 = 110
answer is correct