Q. A parabola opening up or down has vertex (0,−3) and passes through (4,−5). Write its equation in vertex form.Simplify any fractions.______
Identify vertex form: Identify the vertex form of a parabola.The vertex form of a parabola is given by the equation y=a(x−h)2+k, where (h,k) is the vertex of the parabola.
Plug vertex coordinates: Plug the vertex coordinates into the vertex form.Since the vertex is given as (0,−3), we substitute h=0 and k=−3 into the vertex form equation to get y=a(x−0)2−3, which simplifies to y=ax2−3.
Use point to find 'a': Use the point (4,−5) to find the value of 'a'.We know the parabola passes through the point (4,−5), so we substitute x=4 and y=−5 into the equation y=ax2−3 to find 'a'.−5=a(4)2−3−5=16a−3
Solve for 'a': Solve for 'a'.We will isolate 'a' by adding 3 to both sides of the equation and then dividing by 16.−5+3=16a−2=16aa=−162a=−81
Write final equation: Write the final equation of the parabola in vertex form.Now that we have found a to be −81, we substitute it back into the equation y=ax2−3 to get the final equation of the parabola:y=(−81)x2−3
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