HELP 100 POINTS FOR THE RIGHT ANSWER!!!!!!!!!!!!

Answer:
x = 45'
Step-by-step explanation:
angle on a straight line is 180'
(2x +45)+x = 180'
open brackets
2x + 45 + x = 180'
collect like terms
3x +45= 180'
change equation
3x =180' - 45
3x = 135
divide both sides by 3
3x/3 = 135/3
x = 45'