Question 57763
You're close.  Try: (5t + 1)(3t - 4).

Using the distributive property, you will obtain:
15t^2 - 20t + 3t - 4, which simplifies to 15t^2 - 17t - 4.

Then solve for t by setting each factor to zero. That is,
(5t + 1) = 0 and (36t - 4) = 0.

For 5t + 1 to equal zero, then 5t must = -1 (i.e., -1 + 1 = 0), so t = -1/5.

For 3t - 4 to equal zero, then 3t must equal 4 (i.e., 4 - 4 = 0), so t = 4/3.

Therefore, your solution set might be t = { -1/5, 4/3 }

I say "might be" because there may be a constraint.

If t cannot be a negative number, then your only solution is 4/3.

Likewise, if t cannot be a positive number, then your only solution is -1/5.