Just think of slope as the rate of change
6 inches, 1 inch, and 10 inches
The student made error in step 2 because negative multiplied by positive is negative. Also negative multiplied by negative is positive
The answer is :x=3±√3312x=3±3312x≈0.72871355,−0.22871355
Use the quadratic formula to find the solutions.<span><span><span><span>−b</span>±<span>√<span><span>b2</span><span><span>−4</span><span>(<span>ac</span>)</span></span></span></span></span><span>2a</span></span><span><span><span>-b</span>±<span><span>b2</span><span><span>-4</span><span>ac</span></span></span></span><span>2a</span></span></span>Substitute the values <span><span>a=6</span><span>a=6</span></span>, <span><span>b=<span>−3</span></span><span>b=<span>-3</span></span></span>, and <span><span>c=<span>−1</span></span><span>c=<span>-1</span></span></span> into the quadratic formula and solve for <span>xx</span>.<span><span><span>3±<span>√<span><span><span>(<span>−3</span>)</span>2</span><span><span>−4</span>⋅<span>(<span>6⋅<span>−1</span></span>)</span></span></span></span></span><span>2⋅6</span></span><span><span>3±<span><span><span>-3</span>2</span><span><span>-4</span>⋅<span>6⋅<span>-1</span></span></span></span></span><span>2⋅6</span></span></span>Simplify.Tap for less steps...Simplify the numerator.Tap for less steps...Raise <span><span>−3</span><span>-3</span></span> to the power of <span>22</span> to get <span>99</span>.<span><span>x=<span><span>3±<span>√<span>9<span><span>−4</span>⋅<span>(<span>6⋅<span>−1</span></span>)</span></span></span></span></span><span>2⋅6</span></span></span><span>x=<span><span>3±<span>9<span><span>-4</span>⋅<span>6⋅<span>-1</span></span></span></span></span><span>2⋅6</span></span></span></span>Multiply <span>66</span> by <span><span>−1</span><span>-1</span></span> to get <span><span>−6</span><span>-6</span></span>.<span><span>x=<span><span>3±<span>√<span>9<span><span>−4</span>⋅<span>−6</span></span></span></span></span><span>2⋅6</span></span></span><span>x=<span><span>3±<span>9<span><span>-4</span>⋅<span>-6</span></span></span></span><span>2⋅6</span></span></span></span>Multiply <span><span>−4</span><span>-4</span></span> by <span><span>−6</span><span>-6</span></span> to get <span>2424</span>.<span><span>x=<span><span>3±<span>√<span>9+24</span></span></span><span>2⋅6</span></span></span><span>x=<span><span>3±<span>9+24</span></span><span>2⋅6</span></span></span></span>Add <span>99</span> and <span>2424</span> to get <span>3333</span>.<span><span>x=<span><span>3±<span>√33</span></span><span>2⋅6</span></span></span><span>x=<span><span>3±33</span><span>2⋅6</span></span></span></span>Simplify the denominator.Tap for less steps...Rewrite.<span><span>x=<span><span>3±<span>√33</span></span><span>2⋅6</span></span></span><span>x=<span><span>3±33</span><span>2⋅6</span></span></span></span>Multiply <span>22</span> by <span>66</span> to get <span>1212</span>.<span><span>x=<span><span>3±<span>√33</span></span>12</span></span><span>x=<span><span>3±33</span>12</span></span></span>The result can be shown in both exact and approximate form.<span><span>x=<span><span>3±<span>√33</span></span>12</span></span><span>x=<span><span>3±33</span>12</span></span></span><span>x≈0.72871355,<span>−0.22871355</span></span>
