Question 401396
If Mary now is {{{x}}} years old, then her mom is {{{9x}}} years old
In 3 years Mary will be {{{(x+3)}}} years old, then her mom will be {{{5(x+3)}}} years old
If now mom is {{{9x}}} years old, then in 3 year she will {{{9x+3}}} years old
Equation
{{{5(x+3)=9x+3}}} 
{{{5x+15=9x+3}}}
{{{5x-9x=3-15}}}  
{{{-4x=-12}}} 
{{{x=(-12)/(-4)}}}  
{{{x=3}}}  
Mary now is 3 years old, her mom now is {{{9*3=27}}} years old
Answer: 3 and 27