Brainlist. Neeed this ASAP. please its on Simplify Expression and i put the picture below

Answer:
G
Step-by-step explanation:
the perimeter is the sum of all sides so we have
[tex]P=a^{2} -ab+a-2a+a^2+ab\\\\P=(a^2-2a^2+a^2)+(-ab+2b)+a\\\\P=(0a^2)+(ab)+a\\\\P=ab+a[/tex]