I CAN USE FACTS ABOUT THE ANGLE SUMOF TRIANGUSTO SOLVE PROBLEMS
Can some one pls help me

Step-by-step explanation:

a. 1 + 3 + 2= 6

17x + 7x + 5x=  29x

29x + 6= 29(6) + 6

b. 12 - 1= 11

5x + 4x + 4x= 13x

13x + 11= 13(9) + 11

c. 90

3x + 7x= 10x

10x + 90= 10(13) + 90

-10= 4x

divide both sides by 4 to get x by itself

-10/4=4x/4

x= -10/4

reduce the fraction by dividing by 2

-10/2= -5

4/2= 2

x= -5/2, x= - 2 1/2 , x=-2.5