2a + 3b = 5

b = a - 5

What is a and b?

Since you have your b term, you can start off by plugging it in where b is in the first equation.

2a + 3 (a-5) = 5

Distribute the 3 to the "a" and - 5.

2a + 3a - 15 = 5

Now you can combine your "a" terms

5a - 15 = 5

Next you want to get the "a" term alone so you can add 15 to both sides.

5a - 15+15 = 5+15

5a = 20

Now divide both sides by 5 to get your "a" value.

5a = 20

/5

a = 4

Now that you have your "a" value, all you have to do is plug your "a" value into either equation. I personally would choose the second equation since it's easier.

b = 4-5

b = - 1

You can go back and check by plugging your answers back into the first equation as well!

2 (4) + 3 (-1) = 5

8 - 3 = 5

5 = 5

a = 4 and b = - 1