Question

ac Method
15t^ -17t-4
ac=15*4=60

This the ac Method can you help me finished this problem

Answer 1

It is not clear what you mean by the "ac method" or what you are trying to solve. You also don't have an exponent after the t^ . You also have not written an equation, so there is nothing to solve.

Are you trying to solve
15t^2 -17t -4 = 0 ?

Perhaps you are refering to the "b^2 - 4ac) method of solving quadratic equations

You can rewrite the equation as
(5t +1)(3t -4)= 0
which will lead to the solutions
t = 4/3 or -1/5