Question

Find the value of the variable.
All answers

Answer 1

1) x = 8

2) x = 18

3) x = 20

Explanation:

1) 5x = 6x - 8

x = 8

2) 8x - 2 + 2x + 2 = 180

10x = 180

x = 18

3) 5x + 40 = 7x

2x = 40

x = 20

Answer 2

First one.

Since the two angles are congruent through vertical angles theorem,

5x = 6x - 8

5x - 6x = -8

-x = -8

x = 8

Second one.

Use the 180° rule.

(8x - 2) + (2x + 2) = 180

8x - 2 + 2x + 2 = 180

8x + 2x + 2 - 2 = 180

10x = 180

x = 180 / 10

x = 18

Third one.

Vertical angle theorem.

7x = 5x + 40

7x - 5x = 40

2x = 40

x = 40 / 2

x = 20