math word problem

Question

the sum of two numbers is 7. if one number is subtracted from the other, the result is -1. Find the numbers

Answer 1

All we need to do here is translate each of these statements into a mathematical formula.

"The sum of two numbers is 7" would become something like

A + B = 7

"If one number is subtracted from the other, the result is -1" could be

A - B = -1 (in this particular instance, the order of variables doesn't matter)

If we rearrange the second equation to

A = B - 1

and substitute it into the first equation as

(B - 1) + B = 7

we can now solve for B.

2B -1 = 7

2B = 8

B = 4

And now, putting B = 4 into either of our first equations, we can solve for A = 3.

The numbers are 3 and 4. Success!