If <span>a ≥ 0</span><span> then </span><span>√a</span><span> denotes the non negative square root of </span>a<span>.
</span><span>(x-9)^2 = (-(x-9))^2 </span> So both <span>x−9</span><span> and </span><span>−<span>(x−9)</span></span><span> are square roots of </span><span><span>(x−9)</span>2</span><span>, but we want to pick whichever is non negative. </span><span><span> x−9</span>|</span><span> does that for us. </span> Answer should be √<span>(x-9)^2) = x-9</span>
