Let x be one side, ? be another, and x + 7 be the hypotenuse. You find that ? = $\displaystyle \sqrt{14x+49}$. Plug all 3 into the perimeter formula with 392 as the perimeter.A city lot has the shape of a right triangle whose hypotenuse is 7 ft longer than one of the other sides. The perimeter of the lot is 392 ft. How long is each side of the lot?

After some math, I got $\displaystyle 14x + 49 = 4x^2 - 1540x + 148225$. Subtract 14x + 49 and I get $\displaystyle 0=4x^2-1554x+148176$

At this point I'm lost because the numbers I'm getting after plugging it into the quadratic equation are anywhere between 80-90% of the perimeter, which doesn't make sense. If anyone could help, that'd be great.