## Essential University Physics: Volume 1 (3rd Edition)

We know that $U=7.0-8.0x+1.7x^2=3.5$ $\implies 1.7x^2-8.0x+3.5=0$ After solving for x, we obtain: $x=\frac{8.0\pm\sqrt{(8.0)^2-4(1.7)(3.5)}}{2(1.7)}$ $x=0.49m$ $x=0.42m$