Question #576da

2 Answers
Aug 25, 2017

x=-6,x=-4,x=-5,(-5,-1)x=6,x=4,x=5,(5,1)

Explanation:

"to find the x-intercepts solve "x^2+10x+24=0to find the x-intercepts solve x2+10x+24=0

"the factors of 24 which sum to + 10 are + 4 and + 6"the factors of 24 which sum to + 10 are + 4 and + 6

rArr(x+6)(x+4)=0(x+6)(x+4)=0

"equate each factor to zero and solve for x"equate each factor to zero and solve for x

x+6=0rArrx=-6larrcolor(red)" x-intercept"x+6=0x=6 x-intercept

3x+4=0rArrx=-4larrcolor(red)" x-intercept"3x+4=0x=4 x-intercept

"given the parabola in standard form "ax^2+bx+cgiven the parabola in standard form ax2+bx+c

"the x-coordinate of the vertex/ axis of symmetry is"the x-coordinate of the vertex/ axis of symmetry is

x_(color(red)"vertex")=-b/(2a)xvertex=b2a

y=x^2+10x+24" is in standard form"y=x2+10x+24 is in standard form

"with "a=1,b=10,c=24with a=1,b=10,c=24

x_(color(red)"vertex")=-10/2=-5xvertex=102=5

"substitute this value into the equation for y"substitute this value into the equation for y

rArry_(color(red)"vertex")=(-5)^2+10(-5)+24=-1yvertex=(5)2+10(5)+24=1

rArrcolor(magenta)"vertex "=(-5,-1)vertex =(5,1)

"axis of symmetry is "x=-5axis of symmetry is x=5
graph{(y-x^2-10x-24)(y-1000x-5000)=0 [-10, 10, -5, 5]}

Aug 25, 2017

The x intercepts are x_1=-6x1=6 and x_2=-4x2=4
The axis of symmetry is: x=-5x=5
The vertex is V=(-5;-1)V=(5;1)

Explanation:

In order to find the x intercepts, we will substitute y=0y=0 and then solve the equation x^2+10x+24=0x2+10x+24=0.
We will use the short quadratic formula x=-b/2+-sqrt((b/2)^2-cx=b2±(b2)2c, useful when b is even and a=1 in the general form ax^2+bx+c=0ax2+bx+c=0

Then x=-5+-sqrt(5^2-24)=-5+-1x=5±5224=5±1

and the x intercepts are x_1=-6x1=6 and x_2=-4x2=4

The axis of symmetry is:

x=-b/(2a)=-10/2=-5x=b2a=102=5

We simply will get the second coordinate of the vertex by substituting x=-5 in the given F(x):

Then V=(-5;F(-5))=(-5;25-50+24)=(-5;-1)V=(5;F(5))=(5;2550+24)=(5;1)
graph{x^2+10x+24 [-10, 5, -5, 5]}