Which equation is the result of adding these two equations?

2x + 3y = -5
7x - 3y = 9

[A] 5x = 4 [B] 9x = 4
[C] -5x = -14 [D] 9x = 14
[C] -5x = -14

Write the pair of fractions as a pair of fractions with a common denominator

Will mark brainliest! ( explain the answer too, it can be one sentence)

The center on a target has a diameter of 5 inches. the whole target has a diameter of 25 inches. complete the explanation for what part of the whole target is the center. the center of the target takes up % of the whole target.