Another method!
<span><span>Pvertex</span>→<span>(x,y)</span>→<span>(4,9)</span></span>
Explanation:
Given:<span> y=<span>x2</span>−8x+7</span>
This is already in the form <span> y=a<span>(<span>x2</span>+<span>ba</span>)</span>+c as a=1</span>
So we can do this 'trick'
Applying <span><span>x vertex</span>=<span>(−<span>12</span>)</span><span>(<span>ba</span>)</span>→<span>(−<span>12</span>)</span><span>(−8)</span>=+4</span>
<span>To determine <span>yvertex</span></span>
Substitute for <span>x=<span>(−4)</span></span> in the original equation giving:
<span> <span>yvertex</span>=<span><span>(4)</span>2</span>−8<span>(4)</span>+7</span>
<span><span>y vertex</span>=+16−32+7=−<span>9
</span></span>