How do you factor out 4v(squared) - 16v + 7?

It is a square trinomial:
4v^2 - 16v + 7 = 0
lets multiply and divide all by 4, the square term coefficient:
(16v^2 - 16(4)v + 28)(1/4) = 0
(4v - 14)(4v - 2)(1/4) = 0
factor 1/4
(4v - 14)(4v - 2)(1/2)(1/2) = 0
and divide each:
(2v - 7)(2v - 1) = 0

Ibelieve the total for the tip could be $21.90