Please help me with this question
1 answer:
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Given:
The x- intercepts of a parabola are (0,-6) and (0,4).
The parabola crosses the y- axis at -120.
Lucas said that an equation for the parabola is and that the coordinates of the vertex are (-1, -125).
To find:
Whether Lucas is correct or not.
Solution:
The x- intercepts of a parabola are (0,-6) and (0,4). It means (x+6) and (x-4) are the factors of the equation of the parabola.
...(i)
The parabola crosses the y- axis at -120. It means the equation of the parabola must be true for (0,-120).
Divide both sides by -24.
Substituting in (i), we get
So, the equation of the parabola is .
The vertex of a parabola is:
In the equation of the parabola, .
Putting in the equation of the parabola, we get
So, the vertex of the parabola is at point (-1,-125).
Therefore, Lucas is correct.