\(7x\left(x+2\right)-7x\left(x+3\right)=14\)
\(\Leftrightarrow7x\left[\left(x+2\right)-\left(x+3\right)\right]=14\)
\(\Leftrightarrow7x\left(x+2-x-3\right)=14\)
\(\Leftrightarrow7x.\left(-1\right)=14\)
\(\Leftrightarrow-7x=14\)
\(\Leftrightarrow x=\dfrac{14}{-7}\)
\(\Leftrightarrow x=-2\)
Vậy x = -2.
\(7x\left(2+x\right)-7x\left(x+3\right)=14\\ \Leftrightarrow14x+7x^2-7x^2-21x=14\\ \Leftrightarrow-7x=14\Rightarrow x=-2\)
7.x(2+x)-7.x(x+3)=14
=>7.x[(2+x)-(x+3)]=14
=>7x.(-1) =14
=>7x =14:(-1)
=>7x =(-14)
=>x =(-14):7
=>x =(-2)
Vậy x = (-2)
