Let Martha age = x years old
Since her mother's age is 5 times her age, then
Her mother = 5(x) = 5x years old
Since the sum of their ages is 84, then
Add x and 5x, then equate the sum by 84
[tex]\begin{gathered} x+5x=84 \\ 6x=84 \end{gathered}[/tex]Divide both sides by 6 to find x
[tex]\begin{gathered} \frac{6x}{6}=\frac{84}{6} \\ x=14 \end{gathered}[/tex]Martha is 14 years old
