F.2 Maths hw..

Factorize the following expressions
a)
(x^2 + 10x + 25) - (y^2 + 8y +16)
=(x+5)^2-(y+4)^2
=(x+5+y+4)(x+5-y-4)
=(x+y+9)(x-y+1)

b)
(4x^2 + 4x + 1) - (y^2 +6y + 9)
=(2x+1)^2-(y+3)^2
=(2x+1+y+3)(2x+1-y-3)
=(2x+y+4)(2x-y-2)

c)
4x^2 - 12xy + 9y^2 - 16
=(2x-3y)^2-4^2
=(2x-3y+4)(2x-3y-4)

d)
49x^2 - 16y^2 + 8y - 1
=(7x)^2-(4y-1)^2
=(7x+4y-1)(7x-4y+1)

e)
12x^2 - 3y^2 - 8x + 2y
I think something wrong in this question
f)
y^2 - 14y + 48
=(y-6)(y-8)

答案
a) 9
b) -8
c) -16
d) -1
e) 0
f) 48