Answer: -2.8
Explanation:
3t-(8/5) * 4-t < -7
(15t-8)/5 * 4-t < -7
((15t-8)(4-t))/5 < -7
(15t^2)-28t-32< -7
(15t^2)-28t-32-7< 0
(15t^2)-28t-39< 0
Using the quadratic/almighty formula
t= (-b +- ((b^2)-4ac)^(1/2)/2a)
a=15, b=-28, c=-39
t= (-(28) +- (((-28)^2)-4(15)(-39))^(1/2))/2(15))
t= -2.8 or t= 0.9
Since
t<0, then t= -2.8