help please

I'm going to assume that there is an original equation of y=(-1/2)x+b with a y-value of 2 and an x-value of -3, solve for b.

$2=-\frac{1}{2}(-3)+b$

Multiply.

$2=\frac{3}{2}+b$

Subtract b from both sides.

$\frac{4}{2}-\frac{3}{2}=b$

$b=\frac{1}{2}$

Now plug back into original equation.

$y=-\frac{1}{2}x+\frac{1}{2}$

In a problem with mx+b format, m is the slope, or in this problem $m=-\frac{1}{2}$.