a: \(=a^2\left(a+b\right)-ac\left(a+b\right)\)
\(=a\left(a+b\right)\left(a-c\right)\)
b: \(2\left(x+3\right)-x^2-3x\)
\(=2\left(x+3\right)-x\left(x+3\right)\)
\(=\left(x+3\right)\left(2-x\right)\)
c: \(x^3+x^2+x+1\)
\(=x^2\left(x+1\right)+\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2+1\right)\)
d: \(2x\left(3x-5\right)+10-6x\)
\(=2x\left(3x-5\right)-2\left(3x-5\right)\)
\(=2\left(3x-5\right)\left(x-1\right)\)


