a, \(x^2+3x-16\)
\(=x^2+1,5x+1,5x+2,25-18,25\)
\(=\left(x+1,5\right)^2-\left(\sqrt{18,25}\right)^2\)
\(=\left(x+1,5+\sqrt{18,25}\right)\left(x+1,5-\sqrt{18,25}\right)\)
b, \(15x^2-x-6\)
\(=15x^2-10x+9x-6\)
\(=5x\left(3x-2\right)+3\left(3x-2\right)\)
\(=\left(3x-2\right)\left(5x+3\right)\)
c, \(x^2-4x+13\)
Pt này bạn xem lại nha!