find the x-intercepts of the parabola with vertex(-1,-16)and the y-intercept(0,-15)

Algebra
Tutor: None Selected Time limit: 1 Day

find the x-intercepts of the parabola with vertex(-1,-16)and the y-intercept(0,-15).write your answer in this form:(x1,y1)(x2,y2).

Apr 29th, 2015

Vertex = (-1, -16)

y-intercept = (0, -15)


Equation of the parabola in vertex form is

y = a(x-h)^2 + k

where (h, k) is the vertex of the parabola.

So, (h, k) = (-1, -16)


So, equation of the parabola becomes

y = a(x - (-1))^2 + (-16)

y = a(x + 1)^2 - 16


Since (0, -15) is the y-intercept, it must satisfy the above equation

So,

-15 = a(0 + 1)^2 - 16

-15 + 16 = a(1)^2

a = 1


So equation of the parabola is

y = 1(x + 1)^2 - 16

y = (x + 1)^2 - 16


To find the x intercepts, put  y = 0

 (x + 1)^2 - 16 = 0

 (x + 1)^2 = 16

x + 1 =  √16

x + 1 = ± 4

x + 1 = 4     or        x + 1 = -4

x = 4 - 1      or        x = -4 - 1

x = 3           or        x = -5

  

So the x-intercepts are  (3, 0)  and (-5, 0).



Apr 29th, 2015

Studypool's Notebank makes it easy to buy and sell old notes, study guides, reviews, etc.
Click to visit
The Notebank
...
Apr 29th, 2015
...
Apr 29th, 2015
Mar 30th, 2017
check_circle
Mark as Final Answer
check_circle
Unmark as Final Answer
check_circle
Final Answer

Secure Information

Content will be erased after question is completed.

check_circle
Final Answer