The equation of the parabola with vertex at origin, which passes through the point (-3,7) and axis along the x -axis is

Question

The equation of the parabola with vertex at origin, which passes through the point (-3,7) and axis along the x -axis is (A) y2=49 x (B) 3 y2=-49 x (C) 3 y2=49 x (D) x2=-49 y

Tardigrade Admin · Accepted Answer

Let a parabola with vertex at origin and axis along the

x

-axis be

y^{2} = 4 a x

. It passes through

(- 3, 7)

hence

(7)^{2} = 4 a (- 3)

\Rightarrow a = - \frac{49}{12}

.

∴

The required equation of the parabola is

y^{2} = 4 (- \frac{49}{12}) x or 3 y^{2} = - 49 x

Q. The equation of the parabola with vertex at origin, which passes through the point $(- 3, 7)$ and axis along the $x$ -axis is

$y^{2} = 49 x$

$3 y^{2} = - 49 x$

$3 y^{2} = 49 x$

$x^{2} = - 49 y$

Let a parabola with vertex at origin and axis along the $x$ -axis be $y^{2} = 4 a x$ . It passes through $(- 3, 7)$
hence $(7)^{2} = 4 a (- 3)$
$\Rightarrow a = - \frac{49}{12}$ .
$∴$ The required equation of the parabola is
$y^{2} = 4 (- \frac{49}{12}) x or 3 y^{2} = - 49 x$

Q. The equation of the parabola with vertex at origin, which passes through the point (−3,7) and axis along the x -axis is

y2=49x

3y2=−49x

3y2=49x

x2=−49y