Answer:
The polynomial f(x) = x^2 - 8x - 20
The graph of y= - 1/2x+2 is positive over the interval (4, infinity) and negative over the interval (-infinity, 4) .What happens
on the graph when x=4? explain
1 answer:
The graph of y=ax+b, where a≠0, is always a line:
i) increasing if a>0
ii) decreasing if a<0
Consider the decreasing case.
The line is above the x-axis, that is positive but decreasing. At 1 single point it cuts the x-axis, so x=0, and then it continues decreasing below the x-axis.
Back to our problem:
The graph of y=-1/2 x +2 is a decreasing line.,
so it CANNOT be
"positive over the interval (4, infinity) and negative over the interval (-infinity, 4)"
it is
"<span>negative over the interval (4, infinity) and positive over the interval (-infinity, 4)</span>"
the graph is "<span>positive over the interval (-infinity, 4)</span>", it means that the line is decreasing but above the x-axis until 4, (4 not included).
then, "negative over the interval (4, infinity)", which means that the line is now decreasing below the x-axis.
when x=4, the line cuts the x-axis.
check the graph of the line generated using desmos.com
You might be interested in
I have attached a screenshot with the images of the two popcorn bags used by the theater.
Part (a):
Bag A:
Volume of bag = area of base * height
Volume of bag = length * width * height
We have:
volume = 96 in³
length = 3 in
width = 4 in
Therefore:
96 = 3 * 4 * height
96 = 12 * height
height of bag A = 8 in
Bag B:
Volume of bag = area of base * height
Volume of bag = length * width * height
We have:
volume = 96 in³
length = 4 in
width = 4 in
Therefore:
96 = 4 * 4 * height
96 = 16 * height
height of bag B = 6 in
Part (b):
To determine the amount of paper needed, we will need to calculate the surface of each bag. Excluding the top base, each bag will have 5 faces. Four side faces (each two opposite are equal) and the base.
Bag A:
Surface area = area of base + 2*area of front face + 2*area of side face
Surface area = (3*4) + 2(8*4) + 2(8*3)
Surface area = 12 + 64 + 48
Surface area of bag A = 124 in²
Bag B:
Surface area = area of base + 2*area of front face + 2*area of side face
Surface area = (4*4) + 2(6*4) + 2(6*4)
Surface area = 16 + 48 + 48
Surface area of bag B = 112 in²
From the above calculations, we can deduce that the theater should choose bag B in order to reduce the amount of paper needed.
Hope this helps :)
Part (a):
Bag A:
Volume of bag = area of base * height
Volume of bag = length * width * height
We have:
volume = 96 in³
length = 3 in
width = 4 in
Therefore:
96 = 3 * 4 * height
96 = 12 * height
height of bag A = 8 in
Bag B:
Volume of bag = area of base * height
Volume of bag = length * width * height
We have:
volume = 96 in³
length = 4 in
width = 4 in
Therefore:
96 = 4 * 4 * height
96 = 16 * height
height of bag B = 6 in
Part (b):
To determine the amount of paper needed, we will need to calculate the surface of each bag. Excluding the top base, each bag will have 5 faces. Four side faces (each two opposite are equal) and the base.
Bag A:
Surface area = area of base + 2*area of front face + 2*area of side face
Surface area = (3*4) + 2(8*4) + 2(8*3)
Surface area = 12 + 64 + 48
Surface area of bag A = 124 in²
Bag B:
Surface area = area of base + 2*area of front face + 2*area of side face
Surface area = (4*4) + 2(6*4) + 2(6*4)
Surface area = 16 + 48 + 48
Surface area of bag B = 112 in²
From the above calculations, we can deduce that the theater should choose bag B in order to reduce the amount of paper needed.
Hope this helps :)