7x.(2+x)-7x.(x+3)=14
7x.[(2+x)-(x+3)]=14
7x.[x+2-x-3]=14
7x.(-1) =14
7x =14:(-1)
7x =-14
x =-14:7
x =-2
Chúc bn học tốt
\(7x\cdot\left(2+x\right)-7x\cdot\left(x+3\right)=14\)
\(7x\cdot\left(2+x-x-3\right)=14\)
\(7x\cdot\left(-1\right)=14\)
\(7x=-14\)
\(x=-2\)
Ta có : 7x. ( 2+x ) - 7x. ( x+3 ) = 14
<=> 7x . \([(2+x)-\left(x+3\right)]\)=14
<=>7x . \([2+x-x-3]\)=14
<=> 7x. (-1) = 14
<=> 7x = -14
<=> x = -2
Vậy x = -2