Q. A parabola opening up or down has vertex (0,−5) and passes through (−10,20). Write its equation in vertex form.Simplify any fractions.
Vertex Form Explanation: What is the vertex form of the parabola?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.
Equation with Vertex: What is the equation of a parabola with a vertex at (0,−5)?Substitute 0 for h and −5 for k in the vertex form.y=a(x−0)2+(−5)y=ax2−5
Use Point to Find 'a': Use the point (−10,20) to find the value of 'a'.Replace the variables with (−10,20) in the equation.Substitute −10 for x and 20 for y.20=a(−10)2−520=100a−5
Solve for 'a': Solve for a.20=100a−5Add 5 to both sides of the equation.25=100aDivide both sides by 100.10025=a41=a
Write Equation with 'a': Write the equation of the parabola with the value of a found.Substitute 41 for a in the equation y=ax2−5.y=(41)x2−5Vertex form of the parabola: y=(41)x2−5
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