If f(x) = 3x - 8, then evaluate f(2x + 2)?
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Answer:
Intercept form is y= (x+5)(x+3)
vertex is (-4,1)
y intercept is (0,15)
x intercepts are (-5,0) (-3,0)
Step-by-step explanation:
Given quadratic function
To rewrite it in standard form we need to expand (x+4)^2
Intercept form is y=a(x-p)(x-q)
Factor x^2 + 8x + 15
product is 15 and sum is 8, 5*3= 15 and 5+3=8
(x+5)(x+3)
Intercept form is y= (x+5)(x+3)
Vertex form of equation is y=(x-h)^2+k
where (h,k) is the vertex
, here h = -4 and k =1 so vertex is (-4,1)
To find y intercept plug in 0 for x
y= (x+5)(x+3)
y= (0+5)(0+3) = 15, so y intercept is (0,15)
to find x intercept plug in 0 for y
y= (x+5)(x+3)
0= (x+5)(x+3), x+5 =0 and x+3=0
x=-5 and x= -3
So x intercepts are (-5,0) (-3,0)
For this case we have that by definition, the equation of a line in the slope-intersection form is:
Where:
m: It is the slope
b: It is the cut point with the y axis
The slope is:
Thus, the equation is of the form:
We substitute the given point and find "b":
Finally, the equation is:
Answer: