Answer:
[tex]x=\frac{7}{143}[/tex]
Step-by-step explanation:
Simplify the right side of the equation. [tex]3x+21=432x[/tex]. Subtract 21 from both sides of the equation. [tex]3x=432x-21[/tex]. Subtract 432x from both sides of the equation, [tex]-429x=-21[/tex]. The negative signs cancel out to get [tex]429x=21[/tex]. Divide both sides but 429 to get [tex]x=\frac{21}{429}[/tex]. Reduce to get [tex]x=\frac{7}{143}[/tex].