B. 3M-2N
this is because when you combine 4n and -6n you get -2n
You can try finding the roots of the given quadratic equation to get to the solution of the equation.
There are two solutions to the given quadratic equation

<h3>How to find the roots of a quadratic equation?</h3>
Suppose that the given quadratic equation is 
Then its roots are given as:

<h3>How to find the solution to the given equation?</h3>
First we will convert it in the aforesaid standard form.

Thus, we have
a = 1. b = -114, c = 23
Using the formula for getting the roots of a quadratic equation,

Thus, there are two solutions to the given quadratic equation

Learn more here about quadratic equations here:
brainly.com/question/3358603
<h3>
Answer: 10</h3>
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Explanation:
The two smaller triangles are proportional, which lets us set up this equation
5/n = n/15
Cross multiplying leads to
5*15 = n*n
n^2 = 75
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Apply the pythagorean theorem on the smaller triangle on top, or on the right.
a^2+b^2 = c^2
5^2+n^2 = m^2
25+75 = m^2
100 = m^2
m^2 = 100
m = sqrt(100)
m = 10