Question

Find the value of x.

Answer 1

Answer:

x = 20°

Step-by-step explanation:

(4x-10)+x=90

4x-10+x=90

4x+x-10=90

5x-10=90

5x=100

x=20

Answer 2

Answer:

20

Step-by-step explanation:

Straight line angles:

     Angles on a straight line add up to 180°.

 90 + 4x - 10 + x = 180

 90 - 10 + 4x + x = 180

Combine like terms.

         80 + 5x     = 180

Subtract 80 from both sides,

                 5x    = 180 - 80

                    5x = 100

Divide both sides by 5

                      x = 100 ÷ 5

                      $\sf \boxed{x = 20^\circ}$