Step-by-step explanation:
[tex]2 {v}^{2} + 14 = 104 \\ 2 {v}^{2} = 104 - 14 \\ 2 {v}^{2} = 90 \\ {v}^{2} = 90 \div 2 \\ {v}^{2} = 45 \\ v = \sqrt{45} [/tex]
I will leave the answer in square root form as i am not sure if you need to round your answer or not.