Question 140754
Let Frederique's age be F and her brother's, B.
Right now,
1.{{{F=B+2}}}
12 years ago,
2.{{{F-12=2(B-12)}}}
Substitute 1 into 2 and solve for B.
{{{F-12=2(B-12)}}}
{{{(B+2)-12=2(B-12)}}}
{{{B+2-12=2B-24}}}
{{{B-10=2B-24}}}
{{{B-2B=-24+10}}}
{{{-B=-14}}}
{{{B=14}}}
Now that you have the brother's age, you can use a previous formula to find F.
{{{F=B+2}}}
{{{F=14+2}}}
{{{F=16}}}