a)\(x^2+x-6\)
\(=x^2-2x+3x-6\)
\(=\left(x^2-2x\right)+\left(3x-6\right)\)
\(=x\left(x-2\right)+3\left(x-2\right)\)
\(=\left(x-2\right)\left(x+3\right)\)
a) x2 + x - 6
= x2 - 2x + 3x - 6
= (x2 - 2x) + (3x - 6)
= x(x - 2) + 3(x - 2)
= (x + 3)(x - 2)
b) x4 + 4
= x4 + 4x2 + 4 - 4x2
= (x4 + 4x2 + 4) - 4x2
= (x + 2)2 - 4x2
= (x + 2 - 2x)(x + 2 +2x)