Step-by-step explanation:

Factor by grouping,

Complete the square, with the x variables,

Factor out 25 for the y variables

Complete the square

Simplify the perfect square trinomial

Make the right side be 1 so divide everything by 25.

Here our center is (7,2).
One way in which to approach this problem would be to treat it as an equation of ratios and to cross multiply:
<span>[(4x + 15) / 5x)] = 1/2 could be written as:
4x + 15 1
----------- = ---
5x 2
Then 8x + 30 = 5x
3x = -30, and so x = -10 (answer). Be certain to check this answer through substitution!
</span>
Perimeter = 2 1/8 + 3 1/2 + 2 1/2 = 7 (1 + 4 + 4)/8 = 7 9/8 = 8 1/8
A)4/13 would be the larger number since if you were to try to add them, 4/13 = 40/130 and 3/10 = 39/130, 40/130 > 39/130
B) A rational number between them would be 39.5/130.