All the interior angles of a triangle always add up to 180 degrees.
3x + (2x + 20) + (4x - 20) = 180
3x + 2x + 20 + 4x - 20 = 180
3x + 2x + 4x + 20 - 20 = 180
10x = 180
x = 180/10
Therefore, x = 18
Snemsjsjsjjsuduwjrbebsjenwnwnwnnnnnnjjjnnjnbbjjokbbkjvgjjbnnnnkkkkkkkkkkkk
Hi there! The answer is x = -1
Let's solve this equation step by step!

First collect terms.

Subtract (1/2)x from both sides.

Subtract 3 from both sides.

And finally divide by -1 3/4
I got -28.08695652. It doesn't repeat nor does it terminate
216/200=%
1.08 which equals 108%