Q. A parabola opening up or down has vertex (0,−4) and passes through (8,12). Write its equation in vertex form.Simplify any fractions.
Identify Vertex Values: We have:Vertex: (0,−4)Identify the values of h and k.Vertex is (0,−4).h=0k=−4
Select Equation: We have:y=a(x−h)2+kh=0 and k=−4Select the equation after substituting the values of h and k.Substitute h=0 and k=−4 in y=a(x−h)2+k.y=a(x−0)2−4y=ax2−4
Find Value of a: We have: y=ax2−4Point: (8,12)Find the value of a.y=ax2−412=a(8)2−412+4=a×6416=a×646416=64(a×64)a=41
Write Vertex Form: We found:a=41h=0k=−4Write the equation of a parabola in vertex form.y=a(x−h)2+ky=41(x−0)2−4Vertex form: y=41x2−4
More problems from Write a quadratic function from its vertex and another point