Firstly, you can combine like terms, or terms that have the same variable and exponents.
24x and 4x both have the variable "x" so it can be combined to make 28x
A coefficient is basically just the number that's used to multiply the variable
In this case, the variable is "x" and the number that will be multiplied to x is 28.
<em>The coefficient is 28.</em>
The distance between the horizontal legs be the distance between the 'x' values '-5' and '2'. 2+5=7 (It is +5 because the distance between -5 and 0 is 5*)
The distance between the horizontals is 7
Same with the vertical points, as the distance is 2. (1+1=2)
Considering that the pythagorean theorem is the a^2+b^2=c^2, and 'a' and 'b' are the sides, then you plug in '7' and '2', making the equation 7^2+2^2=c^2
49+4=c^2
53=c^2
c=sqrt(53)
Hope this helps.