Answer:
x = 9
y = 6
Step-by-step explanation:
Let's set up equations:
x + y = 15
x - y = 3
Let's rearrange one of these equations to use the substitution method:
x - y = 3
Add y to each side:
x = y + 3
Substitute in for x:
x + y = 15
y + 3 + y = 15
Combine like terms:
( y + y ) + 3 = 15
2y + 3 = 15
Subtract 3 from each side:
2y = 12
Divide each side by 2:
y = 6
Substitute this in to find the other variable:
x + y = 15
x + 6 = 15
Subtract 6 from each side:
x = 9
