Respuesta :
Answer
y = x^2 + 8x + 15 the standard form.
y +1 = (x + 4)(x + 4) intercept form.
Vertex = (-4, -1)
y-intercept is (0, 15)
x-intercept are (-3, 0) and (-5, 0)
Step-by-step explanation:
The given equation is in vertex form.
y = (x + 4)^2 - 1
To write in standard form, we have to expand the above function.
Here we use the formula (a + b)^2 = a^2 + 2ab + b^2
y = x^2+ 2*4*x + 4^2 - 1
y = x^2+ 8x +16 - 1
y = x^2 + 8x + 15 the standard form.
y +1 = (x + 4)(x + 4) intercept form.
Vertex = (h, k) = (-4, -1)
y-intercept
To find the y-intercept, plug in x =0 in the above equation.
y = (0 + 4 )^2 -1
y = 16 - 1
y = 15
y-intercept is (0, 15)
x-intercept
To find the x-intercept plug in y =0 and find the values of x.
(x + 4)^2 -1 =0
(x + 4 )^2 =1
Taking the square root on both sides, we get
x + 4 = ±1
x-intercept are (-3, 0) and (-5, 0)
Hope this will helpful.
Thank you.
Answer:
Standard form - y=x^{2}+8x+15
Intercept form - y=(x+5)(x+3)
The vertex is is (-4,-1)
y intercept=(0,15)
X intercepts (-5,0) and (-3,0)
Step-by-step explanation:
The given quadratic equation is
[tex]y=(x+4)^{2} -1\\y=x^{2}+8x+16-1\\y=x^{2}+8x+15[/tex]
and we know that the standard form of the quadratic equation is
[tex]y=ax^{2}+bx+c[/tex]
so on comparing with it the above is the standard form only and also we can get the value of a (coefficient of [tex]x^{2}[/tex]) and b( coefficient of x) and constant c so we get them as follows
a=1, b=8 c= 15 now ac=16 so the two numbers whose product is 15 and add is 8 are 5,3
so writing the equation in the Intercept form is [tex]y=(x+5)(x+3)[/tex]
now lets find the vertex,now recall that all parabolas are symmetrical. This means that the axis of symmetry is halfway between the x−intercepts or their average.
axis of symmetry [tex]=\frac{-5-3}{2}=\frac{-8}{2}=-4[/tex]
This is also the x−coordinate of the vertex. To find the y−coordinate, plug the x−value into either form of the quadratic equation. We will use Intercept form.
[tex]y=(-4+5)(-4+3)=-1[/tex]
so, the vertex is (-4,-1).
now Vertex form is written as [tex]y=a(x-h)^{2}+k[/tex] , where (h,k) is the vertex and a is the same as in the other two forms.
for Y intercept put x=0 in the given vertex form
y=[tex](0+4)^{2}-1=16-1=15[/tex]
y intercept=(0,15)
for X intercept put y=0 in intercept form
[tex]0=(x+5)(x+3)[/tex]
X intercepts (-5,0) and (-3,0)