a. `6x(x-2015)-x+2015=6x(x-2015)-(x-2015)=(x-2015)(6x-1)`
b. `x^4+4x^2+4=(x^2)^2+2.x^2 .2 +2^2=(x^2+2)^2`
a) \(6x\left(x-2015\right)-x+2015\)
\(=6x\left(x-2015\right)-\left(x-2015\right)\)
\(=\left(x-2015\right)\left(6x-1\right)\)
b) \(x^4+4x^2+4\)
\(=x^4+2\cdot x^2\cdot2+2^2\)
\(=\left(x^2+2\right)^2\)