I need some help factoring part of an equation.

How would I factor -5(t^{2 }- 7t + 49/4). I do believe I have to factor it as a fraction but I have no clue what the fraction should be 2ab should equal -7t and b^{2 }is supposed to equal 49/4.

My guess is.. -5(t - 7/2)^{2}Is that correct?? Since technically 7/2 is 3.5.. And 3.5 x 2 = 7.. And then 7/2^{2 }should equal 49/4.