Q. Put the quadratic into vertex form and state the coordinates of the vertex.y=x2+4x−21Vertex Form: y=Vertex: (□,□)
Identify Vertex Form: Identify the vertex form of a parabola.The vertex form of a parabola is y=a(x−h)2+k, where (h,k) is the vertex of the parabola.
Complete the Square:Complete the square to transform the given quadratic equation into vertex form.Given equation: y=x2+4x−21To complete the square, we need to find a value that, when added and subtracted to the equation, forms a perfect square trinomial with the x2 and 4x terms.
Calculate Value: Calculate the value needed to complete the square.The coefficient of x is 4. Half of this coefficient is 2, and squaring this value gives us 4. We will add and subtract 4 to complete the square.
Rewrite Equation: Rewrite the equation by adding and subtracting the value found in Step 3 inside the parentheses.y=x2+4x+4−4−21y=(x2+4x+4)−25Now, the expression in the parentheses is a perfect square trinomial.
Factor and Simplify: Factor the perfect square trinomial and simplify the equation.y=(x+2)2−25This is the vertex form of the given quadratic equation.
Identify Vertex: Identify the vertex of the parabola from the vertex form.The vertex form of the equation is y=(x+2)2−25, so the vertex (h,k) is (−2,−25).
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