Respuesta :
2/7 (14-28x)=20
multiply each side by 7/2 to get rid of the fraction
7/2* 2/7 (14-28x) = 7/2* 20
simplify
14-28x = 70
subtract 14 from each side
14-14 -28x = 70-14
-28x = 56
divide each side by -28
-28x/-28 = 56/-28
x= -2
[tex]\dfrac{2}{7}(14-28x)=20\qquad\text{use distributive property}\\\\\dfrac{2}{7}\cdot14-\dfrac{2}{7}\cdot28x=20\\\\2\cdot2-2\cdot4x=20\\\\4-8x=20\qquad\text{subtract 4 from both sides}\\\\-8x=16\qquad\text{divide both sides by (-8)}\\\\\boxed{x=-2}[/tex]