Q. Complete the square to re-write the quadratic function in vertex form:y=x2−x−7Answer: y=
Focus on x-terms: To complete the square and rewrite the quadratic function in vertex form, we first need to focus on the x-terms. The vertex form of a quadratic function is y=a(x−h)2+k, where (h,k) is the vertex of the parabola. We will manipulate the given function to match this form.
Find completing square value: The coefficient of x2 is 1, which is already in the form we need. We will now take the coefficient of x, which is −1, divide it by 2, and square it to find the value that completes the square.(−21)2=41
Add/subtract to complete square: We add and subtract this value inside the parentheses to complete the square, making sure the equation remains balanced.y=x2−x+(41)−(41)−7
Rewrite equation with grouping: Now we can rewrite the equation grouping the x-terms and the constant that completes the square, and moving the other constants outside the parentheses.y=(x2−x+41)−41−7
Factor perfect square trinomial: The expression inside the parentheses is now a perfect square trinomial, which can be factored into (x−21)2.y = (x−21)2−41−7
Combine constants to simplify: Combine the constants −41 and −7 to simplify the equation. Since −7 is equivalent to −428, we have:y=(x−21)2−41−428y=(x−21)2−429
Quadratic function in vertex form: The quadratic function is now in vertex form, with the vertex being the point (h,k)=(21,−429).
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