Answer:
u=-4/3 , u=-1
Step-by-step explanation:
[tex] {3u}^{2} + 7u + 4 = 0 \\ {3u}^{2} + 3u + 4u + 4 = 0 \\ 3u(u + 1) + 4(u + 1) = 0 \\ (3u + 4) = 0 \: and \: (u + 1) = 0 \\ 3u = - 4 \: and \: u = - 1 \\ therefore \: u = \frac{ - 4}{3} and \: u= - 1[/tex]