Q. Complete the square to re-write the quadratic function in vertex form:y=x2−7x−5Answer: y=
Form Perfect Square Trinomial: To complete the square, we need to form a perfect square trinomial from the quadratic and linear terms of the function y=x2−7x−5. We will add and subtract the square of half the coefficient of x inside the parentheses.
Calculate and Add/Subtract: First, we take the coefficient of x, which is −7, divide it by 2 to get −27, and then square it to get (−27)2=449. We will add and subtract this value inside the equation.
Rewrite Function with Added Terms: We rewrite the function by adding and subtracting 449 inside the equation:y=x2−7x+449−449−5
Group and Combine Constants: Now, we group the perfect square trinomial and combine the constants:y=(x2−7x+449)−449−5
Factor Perfect Square Trinomial: Next, we factor the perfect square trinomial:y=(x−27)2−449−5
Convert Constant to Common Denominator: To combine the constants, we need a common denominator. The common denominator for 4 and 1 (since 5 can be written as 5/1) is 4. So we convert −5 to −20/4:y=(x−27)2−449−420
Combine Constants: Now, we combine the constants −449 and −420:y=(x−27)2−469
Write in Vertex Form: The quadratic function is now written in vertex form, which is y=a(x−h)2+k, where (h,k) is the vertex of the parabola. In this case, a=1, h=27, and k=−469.
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