Answer:
x = 16
Step-by-step explanation:
angles 3 and 6 are same side interior angles which means that they are supplementary (add up to 180 degrees)
so we can set it up like this:
(8x - 13) + (4x + 1) = 180
combine like terms
12x - 12 = 180
solve
12x = 192
192/12 = 16
so x = 16
