Question

Please help! Please explain how to do this, I am so lost.

Answer 1

Ok, so we know that RST is equal to 6x+12
And RST is also equal to 78 + 3x-12
so we set them equal to each other

6x + 12 = 3x - 12 + 78
And simplify
3x = 54
x = 18

Finally, we solve for the angle with 18 for x

6(18) + 12
108 + 12
120

Hope this helps