Answer:
x = 5.5
y = - 6.5
Explanation:
Let one of the numbers = x
Let the other number = y
x + y = - 1
x = y + 12 Put the second equation into the first one
y + 12 + y = - 1 Subtract 12 from both sides
y + y = - 1 - 12 Combine both left and right sides
2y = - 13 Divide by 2
2y/2 = - 13/1
y = - 6.5
x + y = - 1
x - 6.5 = - 1 Add 6.5 to both sides
x = 5.5