Answer:
19. x = 65
20. x = 12
21. x = 35, y = 85
Step-by-step explanation:
19. 2x -10 = 120
2x (-10 + 10) = (120 +10)
2x/2 = 130/2
x = 65
20. 2x + 4x + 108 = 180
6x + (108 - 108) = (180 - 108)
6x/6 = 72/6
x = 12
21. 2x + 25 = 3x - 10
2x + (25 - 25) = 3x (- 10 - 25)
(2x - 3x) = (3x - 3x) - 35
-x/-1 = -35/-1
x = 35
3x - 10 + y = 180
3(35) - 10 + y = 180
105 - 10 + y = 180
(95 - 95) + y = (180 - 95)
y = 85
