Answer:
The standard form of a quadratic equation is:
, 
Quadratic Formula Derivation:



Completing the Square:


Square Root property:



the 3rd vertex is on the x axis line which means Y =0
since the longer leg is twice as long as the shorter leg and the length of the shorter leg is a, then twice the length would be 2a ( 2 times a)
so the 3rd vertex is (2a,0)
Step One - List the factors of 60.
Step Two - Locate the factors that are seven apart from each other.
Factors of 60:
1 × 60
2 × 30
3 × 20
4 × 15
5 × 12
6 × 10
60 - 1 = 59
30 - 2 = 28
20 - 3 = 17
15 - 4 = 11
12 - 5 = 7
10 - 6 = 4
5 is 7 less than 12, and 60 is their least common multiple.
Answer: 5 and 12
The answer is B (Sorry for the bad handwriting.)
That's already rounded to the nearest hundredth, so the answer is 3419.46.
The picture below will help you.