Answer:
x = 20
Step-by-step explanation:
2x+7+13 = 3x
2x - 2x +7 +13 = 3x - 2x
20 = x
It is more simple to understand the fact that you should use multiplication and subtraction because it's easier to use.
Angles 1 and 8 are created by line t intersecting with line m.
Line t is called a transversal line, because it intersects 2 parallel lines.
t divides the straight angle formed by m alone, forming the linear pair of angles (1) and (8), whose sum is 180 °, that is they are supplementary.
Answer: (1) and (8) are linear pairs