Answer:
[tex]\frac{-c+d}{b}[/tex]
Step by Step:
Step 1: Subtract c from both sides:
ab + c + (−c) = d + (−c)
ab = −c + d
Step 2: Divide both sides by b:
[tex]\frac{ab}{b} = \frac{-c+d}{b}[/tex]
Step 3: Simplify:
a = [tex]\frac{-c+d}{b}[/tex]
