Question

What is the value of x ?

Answer 1

Answer:
x=70

Note: both angles add up to 180 because it forms a straight line

Step-by-step

x-31+2x+1=180
3x-30=180
3x=180+30
3x=210
3x/3=210/3
x=70

Answer 2

x = 70

Explanation:

Both angles must add up to 180°, by the definition of a line.

Step 1: Set up equation

x - 31 + 2x + 1 = 180

Step 2: Solve for x

3x - 30 = 180

3x = 210

x = 70