One number is 3 more than another. Their sum is - 13. Find the numbers

According to the question if we take one number as a M and 3 more than other represent m+3

so the equation will be : m + (m+3) = - 13

2m+3=-13

2m=-16

m=-8 (one number)

to get another number plug in - 8 for m and that gives us - 8+3=-5

prove if we pluged in all than we get the same result,-8-5=-13

that was the prove of that math hopefully you get it