Answer :
We are given the following equation and want to find which value of x will make it true:
[tex]3-6x=21[/tex]
Subtract 3 from both sides
[tex]-6x=18[/tex]
Divide both sides by -6
[tex]x=-3[/tex]
Thus, the value that will make 3-6x=21 is x=-3. Let me know if you need any clarifications, thanks!
~ Padoru