Factorization: the square C of 18 (a + b) and the square C of 2 (a-b)
The square of 18 (a + b) C-2 (a-b) C
=2c[9(a+b)²-(a-b)²]
=2c[(3a+3b)²-(a-b)²]
=2c(3a+3b+a-b)(3a+3b-a+b)
=2c(4a+2b)(2a+4b)
=8c(2a+b)(a+2b)
AC minus BC + a square minus b square. Factorization
ac-bc+a²-b²
=c(a-b)+(a²-b²)
=c(a-b)+(a+b)(a-b)
=(a-b)(c-a-b)
Factorization a-square-b-square + AC BC
(a-b)(a+b+c)