Question 77874
Let x=Aria's age now
Then x-1=Aria's age last year

And x+14=Beth's age now

And (x+14)-1=Beth's age last year

Now we are told that:

(x+14)-1=3(x-1)  get rid of parens 

x+14-1=3x-3 or
x+13=3x-3  subtract 13 and also 3x from both sides

x-3x+13-13=3x-3x-3-13  collect like terms

-2x=-16  divide both sides by -2

x=8----------------------Aria's age now---------ans

CK
x+14=8+14=22 Beths age now
x+14-1=x+13=8+13=21 Beths age last year
x-1=8-1=7------------------Aria's age last year

Last year Beth was three times as old as Aria
21=7*3
21=21
also
8+14=22
22=22

Hope this helps---ptaylor