Question

Solve the compound inequality
3t-8/5 and 4-t<-7

Answer 1

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