Answer:
x = 9
x+7 = 16
Explanation:
The triangles in this geometry are similar, so the ratios of corresponding sides are proportional.
long side/short side = (x+7)/12 = 12/x
x(x +7) = 12²
x +7x -144 = 0 . . . . . subtract 144 to put in standard form
(x +16)(x -9) = 0 . . . . factor
x = 9 . . . . . . only the positive solution is useful here
The missing lengths are ...