hasil dar (5a-6+ab)-(a+2ab-1)

(5a-6+ab)-(a+2ab-1)
= 5a-6+ab-a-2ab+1
= (5a-a) + (-6+1) + (ab-2ab)
= 4a-5+(-ab)
= 4a-ab-5
atau
= 4a-ab = 5

semoga membantu, maaf kalau salah