Math
posted by tyler on .
The sum of twice a number and another number is 24. The difference of twice the first number and the other number is 12. Which system would model this situation, and what is the solution?

x = 1st number and y = second number
2x + y = 24
2x  y = 12
Can you finish from here? Add the two equations to eliminate y and solve for x.
Then find y.
Be sure to check both x and y in both equations to be sure you are correct. 
2 x + y = 24
y  2x = 12
4 x = 12
x = 3
y = 24  6 = 18
check
6 + 18 = 24 yes
18  6 = 12 yes
note you could have written
2 x + y = 24
2 x  y = 12
2 y = 12
y = 6
2x + 6 = 24
x = 9