Solving quadratics

the value of danielle's investments is modeled by the equation v (t)=3t^2+70t+100
where t represents the number of months after she made her initial investment. jeffrey has no money invested in stocks, but he deposits the same amount every month into a savings account that he opened at the same time as danielle. his savings account balance can be modeled by the equation v (t)=50t+275

after how many months will the value of danielle's investment be equal to jeffery's savings account?