The question says evaluate 2a-b/b when a=4 and b=-3.
How would I start this problem?

You would start by writing down the expression that you have to evaluate:

2a - b/b

Then, get to work:
- Wherever you see ’a’, put in 4.
- Wherever you see ’b’, put in -3.

2(4) - (-3/-3)

Can you handle that?

The thing on the right is a fraction with the same number on top and bottom.
Any fraction like that is always equal to ’ 1 ’.

\( \frac{2a-b}{b}\\\\substitute\ a=4;\ b=-3:\\\\\frac{2\cdot4-(-3)}{-3}=\frac{8+3}{-3}=-\frac{11}{3}=-3\frac{2}{3} \)

\( or\ if\ 2a+\frac{b}{b}=2a+1\ then\ for\ a=4\ and\ b=-3:\\\\2\cdot4-3=8-3=5 \)