Question

What is x for number 14.

Answer 1

x^2
`(x+7)^2=x^2+10^2 x^2+14x+49=x^2+100 14x+49=100 14x=51 x=3.64`

Answer 2

It's a right triangle. So

(x²) + (10²) = (7+x)²

x² + 100 = 49 + x² + 14x

That may look ugly, but I'm pretty sure you can handle it from this point.

Wow ! I just noticed that you can subtract x² from each side
and not even have to mess with it again.