Question

3x . (x + 5) - 3x - 15=0

Answer 1

\(3x\left(x+5\right)-3x-15=0\)

\(\Rightarrow3x\left(x+5\right)-3\left(x+5\right)=0\)

\(\Rightarrow3\left(x+5\right)\left(x-1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=-5\\x=1\end{matrix}\right.\)

Answer 2

\(3x\left(x+5\right)-3x-15=0\\ \Rightarrow3x\left(x+5\right)-3\left(x+5\right)=0\\ \Rightarrow\left(3x-3\right)\left(x+5\right)=0\\ \Rightarrow\left[{}\begin{matrix}3x-3=0\\x+5=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=1\\x=-5\end{matrix}\right.\)