• Apr 22nd 2007, 08:27 PM
georgiaaa.
sorry, last one i swear!

Find the points of intersection between the porabola and line:

y = x^2 + 12x + 24
y = 4x + 9

:confused: !!
i thought i had more brain cells than that!
• Apr 22nd 2007, 09:00 PM
Soroban
Hello, georgiaaa!

Quote:

Find the points of intersection of the parabola and line:
. . y .= .x² + 12x + 24
. . y .= .4x + 9

To find the intersection of two curves, equate the functions.

. . x² + 12x + 24 .= .4x + 9

. . . x² + 8x + 15 .= .0

. . (x + 3)(x + 5) .= .0

And we have: .x = -3, -5

The corresponding values are: .y = -3, -11

Therefore, the intersections are: .(-3,-3) and (-5,-11)

• Apr 22nd 2007, 09:02 PM
Jhevon
Quote:

Originally Posted by georgiaaa.
sorry, last one i swear!

Find the points of intersection between the porabola and line:

y = x^2 + 12x + 24
y = 4x + 9

:confused: !!
i thought i had more brain cells than that!

the parabola and the line will intersect where:

x^2 + 12x + 24 = 4x + 9
=> x^2 + 8x + 15 = 0
=> (x + 5)(x + 3) = 0
=> x = -5 or x = -3

when x = -5
y = 4(-5) + 9 = -11

when x = -3
y = 4(-3) + 9 = -3

so they intersect at (-5,-11) and (-3,-3)

EDIT: Beaten again!