When money is invested at 4.5% simple interest for 4 months, the interest is $105. find the principal

Use the equation to find principal. P= A/(1+r/n)^(n)(t)
A= 105
r= 0.045 (remember you have to change percentage to a decimal)
n=12 (there are 12 months in a year)
t= 4 (number of months)
Plug this into your calculator
105/(1+ 0.045/12)^(12)(4)