1:Replace the variables in the theorem with the values of the known sides.
2:Square the measures, and subtract from each side
3: find the square root of each side
Answer:
What is the question here?
Step-by-step explanation:
Answer: 
This is the shorthand way of writing 
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Work Shown:

The plus or minus is needed because squaring a negative leads to a positive. As another example, x^2 = 25 has x = 5 and x = -5 as the two solutions. Note that x^2 = (-5)^2 = (-5)*(-5) = 25.
Also, note that the 80 was broken up into 16*5. This was done to simplify the square root. We pull out the largest factor that's a perfect square.
So that's how we get to the solution set
. The curly braces tell the reader that they are dealing with a set.
3:5 because if there's a 2:5 chance of grabbing a red card then just subtract 2 from 5 and you get 3:5