Answer: Option b

Step-by-step explanation:
Linear equations have the following form:

Where the exponents n, m, s and h are always 0 or 1
To know which equations are nonlinear, identify among the options given, those that have exponents other than 1 or 0
Note that in option b) the exponent of the variable x is
therefore the equation is nonlinear
Finally the answer is the option b

We need to solve for x, we need to get x alone

Lets start by removing -5
Add 5 on both sides


Now to isolate x , we need to remove the square from x
To remove square , take square root on both sides

square and square root will get cancelled

So
and 
P=5 because the parenthesis mean multiplication, and when you multiply 3 times 5, you receive a product of 15. Then, 15-4 is 11, meaning that p=5.