The sum of all the angles of a triangle is 180°
This means you have to add all the angles together and set it equal to 180. Here is the formula:
50 + 2x + 3x - 10 = 180
Now you solve for x
Step 1: Combine like terms
(50 + (-10) ) + (2x + 3x) = 180
40 + 5x = 180
Step 2: Subtract 40 to both sides
(40-40) + 5x = 180 - 40
5x = 140
Step 3: Isolate x by dividing 5 to both sides
![(5x)/(5) = (140)/(5)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/yw76sxwxck45qblknv2s2h1qu8ztcafjp4.png)
x = 28
Check: 50 + 2(28) + 3(28) - 10 = 180
50 + 56 + 84 - 10 = 180
180 = 180
Therefore your value of x is 28!
Hope this helped!