Question

Find the value of x that will make A||B

Thanks for helping. :)

Answer 1

x = 20

Explanation:

The converse of the same side exterior angles theorem states that when two same side exterior angles are supplementary, the two lines they are on are parallel.

So that means that 5x + 9 and 3x + 11 are supplementary.

Therefore, 5x + 9 + 3x + 11 = 180.

Add like terms: 8x + 20 = 180

Subtract: 8x = 160

Divide: x = 20

Answer 2

*To be honest, we have a bunch of ways to find x, but I'm only going to use one.

So in order for A║B, we need the outer angle of these two lines but on the opposite sides to be equal, which means:

5x + 9 = 180 - (3x + 11)

⇔ 5x + 3x = 180 - 9 - 11

⇔ 8x = 160

⇔ x = 160/8 = 20

So x is equal to 20.