This graph the answer to your problem.
Answer: ab+a-b
ab+ac-a2
CLT( collect like terms)
ab+a2+ac-bc
ab+a-b.
Hope this is correct
Just count, its really simple...its hard to explain using a keyboard tho...sorry i wasnt much help
♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️




♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️