You can put this solution on YOUR website! Algebraically:
If my age is x, my age in 2 years can be represented as x+2
Then:
5(x+2)=100
5x+10=100
5x+10-10=100-10
5x+0=90
5x=90
5x/5=90/5
x*1=18
x=18
Substitute this value back into the original equation to make sure it is correct.