It may help to draw a picture, like the one in the previous example. Since the garden is a right triangle, we know the Pythagorean Theorem must hold. So, we can substitute $15$ in for $a\text{,}$ in the Pythagorean Theorem, and $x$ for $b\text{,}$ which represents the length of the other leg. Then, we can substitute $2x+1$ in for $c\text{,}$ which represents the length of the hypotenuse. Plugging these into the formula will give us: $$(\substitute{15})^2+(\substitute{x})^2=(\substitute{2x+1})^2$$ Simplify both sides: $$\begin{gathered} 225+x^2=(2x+1)(2x+1)\\ 225+x^2=4x^2+4x+1 \end{gathered}$$ As you can see, this is a quadratic equation. So, we will solve this equation by factoring. First, we’ll need to get it into standard form and then we can use the Zero Product Property. $$\begin{gathered} 0=3x^2+4x-224=0\\ 0=(3x+28)(x-8) \end{gathered}$$ $$\begin{aligned} 3x+28\amp=0\amp\amp\text{or}\amp x-8\amp=0\\ x\amp=-\frac{28}{3}\amp\amp\text{or}\amp x\amp=8 \end{aligned}$$ Of course, a negative length doesn’t make sense, so we’ll ignore the negative solution. Thus, the length of the other leg is $8$ feet long, which means the hypotenuse is one foot more than $16$ feet long. Therefore, the length of the hypothenuse is $17$ feet.