Question

(a-7)²+(a-3)(a+3)-18a

Answer 1

( a - 7)² + ( a - 3)(a + 3) - 18a = a² - 14a + 49 + a² - 9 - 18a = 2a² - 32a + 40=
= 2( a² - 16a + 20)

Answer 2

(а-7)²+(а-3)(а+3)-18а=
= а²-14а+49+а²-9-18а=
2a²-32a+40= 2(a²-16a+20)