(−a)(b)+8a−5−((−8a)(b)−4)
So first
Distribute the Negative Sign:
=(−a)(b)+8a−5+−1((−8a)(b)−4)
=(−a)(b)+8a+−5+−1((−8a)(b))+(−1)(−4)
=(−a)(b)+8a+−5+8ab+4=−ab+8a+−5+8ab+4
Then after all of that
Combine Like Terms:=−ab+8a+−5+8ab+4
=(−ab+8ab)+(8a)+(−5+4)
So now your answer is =7ab+8a+−1
