1/4 (v - 7) = 2
1/4v - 1/4 (7/1) = 2
1/4v - 7/4 = 2
1/4v = 15/4
Multiply by 4/1 on both sides to get v
(4/1) 1/4v = 15/4 (4/1)
v = 60/4
v = 15
Let
and
. Then


and


The expression under the square root can be rewritten as

Recall that

so that

and assuming
and
, we end up with

so that

as required.
Not too sure if i can tell u much but the answer on my test is B
Simple,
writing out the problem...

Simplify it...
-4x(6+5-1)
-4x(11-1)
-4x(10)
-40x
Making it look like...

Cancel out the common factors...
Thus making the answer:

.