SOLUTION: Translate to a system of equations and solve. The sum of two numbers is 8. Their difference is 12. Find the number. So far I have: x+y= 30 x-y= 12 I don't kn

Algebra ->  Expressions-with-variables -> SOLUTION: Translate to a system of equations and solve. The sum of two numbers is 8. Their difference is 12. Find the number. So far I have: x+y= 30 x-y= 12 I don't kn      Log On


   

Question 651531: Translate to a system of equations and solve.
The sum of two numbers is 8. Their difference is 12. Find the number.
So far I have: x+y= 30
x-y= 12
I don't know what I have to do to solve for the numbers.
Found 2 solutions by rfer, MathLover1:
Answer by rfer(16322) About Me  (Show Source):
You can put this solution on YOUR website!
x+y=8 y=-x+8
x-y=12
x-(-x+8)=12
2x-8=12
2x=12+8
x=20/2
x=10
--------------
10-y=12
-y=12-10
-y=2
y=-2
--------------
10-2=8
I don't know where you got the 30 from.

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

x%2By=+30....1
x-y=+12....2
__________________
you can solve this system by addition; add 1 and 2
x%2By=+30....1
+
x-y=+12....2
_____________________
x%2Bx%2By%2B%28-y%29=30%2B12
2x%2Bcross%28y%29%2B%28-cross%28y%29%29=42
2x=42
x=42%2F2
highlight%28x=21%29
now find y
21%2By=+30....1
y=+30-21
highlight%28y=+9%29