Math...Factorize

a)Factorize2b^2-15b+18

=(2b-3)(b-6)

b.)Use the result of a),factorize2(2a^2-a)^2-15(2a^2-a)-18

Let b = 2a^2 - a = a(2a-1)

By a): 2(2a^2-a)^2-15(2a^2-a)-18

= [2*a(2a-1) - 3][a(2a-1) - 6]

= (4a^2 - 2a - 3)(2a^2 - a - 6)

= (a-2)(2a+3)(4a^2 - 2a - 3)

2) (xy+y)+x+1

= y(x + 1) + (x + 1)

= (x+1)(y+1)