Answer:
19
Explanation:
When 2 chords intersect then the product of the parts of one chord equal the product of the parts of the other chord, that is
12(x - 7) = 4(x + 3) ← distribute parenthesis on both sides
12x - 84 = 4x + 12 ( subtract 4x from both sides )_
8x - 84 = 12 ( add 84 to both sides )
8x = 96 ( divide both sides by 8 )
x = 12
Thus
12 + x - 7 = 12 + 12 - 7 = 17
4 + x + 3 = 4 + 12 + 3 = 19 ← longer chord