Answer: x = 13 and y = 8
Step-by-step explanation:
Two numbers must add to 21. We don't know them yet, so let's just use a placeholder for both of them for now.
x + y = 21
Their difference is five, meaning that if we subtract one from the other, we get five. Again, we don't know the numbers yet, so we'll add a placeholder for now.
x - y = 5
We can now solve a system of equations for x.
x = y + 5
y + 5 + y = 21
2y + 5 = 21
2y = 16
y = 8
x - 8 = 5
x = 13
So x = 13 and y = 8
