\(3x^2-14x-5=3x\left(x-5\right)+\left(x-5\right)=\left(x-5\right)\left(3x+1\right)\)
\(3x^2-14x-5\)
\(=3x^2-15x+x-5\)
\(=3x\left(x-5\right)+x-5\)
\(=\left(x-5\right)\left(3x+1\right)\)
A= 3x^2 + 14x - 15
3A= (3x)^2 + 2.7.(3x) - 15.3
3A= (3x+7)^2 +(15.3-7.7)
3A= (3x+7 )^2 -2^2
3A= (3x+7-2 )((3x+7+2 )
A= ( 3x-5)( x+ 3)
\(3x^2-14x-5\)
\(=3x^2-15x+x-5\)
\(=\left(x-5\right)\left(3x+1\right)\)