Question

how do I solve a+18=7a ?

Answer 1

$a+18=7a \ \ \ |\hbox{subtract 7a from both sides} \\ -6a+18=0 \ \ \ |\hbox{subtract 18 from both sides} \\ -6a=-18 \ \ \ |\hbox{divide both sides by (-6)} \\ a=3$

Answer 2

$a+18=7a$

$18=7a-a$

$18=6a$ ⇒ $a= \frac{18}{6}$

$\boxed {a=3}$