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For which value of k does the graph of y = x² - 10x + k touch the x-axis at exactly one point?

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For which value of $k$ does the graph of $y = x^2 - 10x + k$ touch the x-axis at exactly one point? What is that point?

Need a reminder? The key ideaShow

$y = ax^2 + bx + c$ has its vertex at $x = -\dfrac{b}{2a}$ and opens upward when $a > 0$ . Completing the square, $a(x - h)^2 + k$ , gives the vertex $(h, k)$ and the range.

The worked solution

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For which value of k does the graph of y = x² - 10x + k touch the x-axis at exactly one point?

The worked solution

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