Find the equation of the parabola with the given x-intercepts and point on the graph. Use y = a(x-p)(x-q).

1. x-int: (-2,0) , (5,0)
P (3,6)

Respuesta :

Answer:

Below

Step-by-step explanation:

a(x-p)(x-q)        p = -2    q = 5

a ( x- - 2)(x - 5)         sub in the values of the point given (3,6) to calculate 'a'

6  = a (3+2)(3-5)

a = -6 /10 = - 3/5

y = -3/5 (x+2)(x-5)  

Answer:

[tex]\textsf{Intercept form}: \quad y=-\dfrac{3}{5}(x+2)(x-5)[/tex]

[tex]\textsf{Standard form}: \quad y=-\dfrac{3}{5}x^2+\dfrac{9}{5}x+6[/tex]

Step-by-step explanation:

[tex]\boxed{\begin{minipage}{6 cm}\underline{Intercept form of a quadratic equation}\\\\$y=a(x-p)(x-q)$\\\\where:\\ \phantom{ww}$\bullet$ $p$ and $q$ are the $x$-intercepts. \\ \phantom{ww}$\bullet$ $a$ is some constant.\\\end{minipage}}[/tex]

If the x-intercepts are (-2, 0) and (5, 0) then:

  • p = -2
  • q = 5

Substitute the values of p and q into the formula:

[tex]\implies y=a(x-(-2))(x-5)[/tex]

[tex]\implies y=a(x+2)(x-5)[/tex]

To find a, substitute the given point on the curve P (3, 6) into the equation:

[tex]\implies 6=a(3+2)(3-5)[/tex]

[tex]\implies 6=a(5)(-2)[/tex]

[tex]\implies 6=-10a[/tex]

[tex]\implies a=\dfrac{6}{-10}[/tex]

[tex]\implies a=-\dfrac{3}{5}[/tex]

Substitute the found value of a into the equation:

[tex]\implies y=-\dfrac{3}{5}(x+2)(x-5)[/tex]

Expand to write the equation in standard form:

[tex]\implies y=-\dfrac{3}{5}(x^2-3x-10)[/tex]

[tex]\implies y=-\dfrac{3}{5}x^2+\dfrac{9}{5}x+6[/tex]