Answer:
D. x = 15, y = 5
Step-by-step explanation:
x + y = 20 (1)
3x - 3y = 30 (2)
From (1)
x = 20 - y
Substitute x = 20 - y into (2)
3x - 3y = 30 (2)
3(20 - y) - 3y = 30
60 - 3y - 3y = 30
- 3y - 3y = 30 - 60
-6y = -30
y = -30/-6
y = 5
Substitute y = 5 into (1)
x + y = 20 (1)
x + 5 = 20
x = 20 - 5
x = 15
x = 15, y = 5
