\(7x\left(x+2\right)-7x\left(x+3\right)=14\)
\(\Leftrightarrow7x\left[\left(x+2\right)-\left(x+3\right)\right]=14\)
\(\Leftrightarrow7x\left(x+2-x-3\right)=14\)
\(\Leftrightarrow7x.\left(-1\right)=14\)
\(\Leftrightarrow-7x=14\)
\(\Leftrightarrow x=\dfrac{14}{-7}\)
\(\Leftrightarrow x=-2\)
Vậy x = -2.
