a: \(=\left(x-y\right)\left(2x^2-y-1\right)\)
b: =(2x-3)(2x+3)
c: \(=x\left(x^2-9\right)+xy\left(x+3\right)\)
\(=x\left(x+3\right)\left(x-3+y\right)\)
d: =(x+3)(x+4)
a: =(x−y)(2x2−y−1)=(x−y)(2x2−y−1)
b: =(2x-3)(2x+3)
c: =x(x2−9)+xy(x+3)=x(x2−9)+xy(x+3)
=x(x+3)(x−3+y)=x(x+3)(x−3+y)
d: =(x+3)(x+4)
a) 2x²(x - y) + y(x - y) - x + y
= 2x²(x - y) + y(x - y) - (x - y)
= (x - y)(2x² + y - 1)
b) 4x² - 9
= (2x)² - 3²
= (2x - 3)(2x + 3)
c) x³ + x²y + 3xy - 9x
= (x³ - 9x) + (x²y + 3xy)
= x(x² - 9) + xy(x + 3)
= x(x - 3)(x + 3) + xy(x + 3)
= x(x + 3)(x - 3 + y)
d) x² + 7x + 12
= x² + 3x + 4x + 12
= (x² + 3x) + (4x + 12)
= x(x + 3) + 4(x + 3)
= (x + 3)(x + 4)
