<h2>Answer-Average rate of change(A(x)) of f(x) over a interval [a,b] is given by:</h2><h2 /><h2>A(x) = \frac{f(b)-f(a)}{b-a}A(x)= </h2><h2>b−a</h2><h2>f(b)−f(a)</h2><h2> </h2><h2> </h2><h2 /><h2>Given the function:</h2><h2 /><h2>f(x) = 20 \cdot(\frac{1}{4})^xf(x)=20⋅( </h2><h2>4</h2><h2>1</h2><h2> </h2><h2> ) </h2><h2>x</h2><h2> </h2><h2 /><h2>We have to find the average rate of change from x = 1 to x= 2</h2><h2 /><h2>At x = 1</h2><h2 /><h2>then;</h2><h2 /><h2>f(x) = 20 \cdot(\frac{1}{4})^1 = 5f(x)=20⋅( </h2><h2>4</h2><h2>1</h2><h2> </h2><h2> ) </h2><h2>1</h2><h2> =5</h2><h2 /><h2>At x = 2</h2><h2 /><h2>then;</h2><h2 /><h2>f(x) = 20 \cdot(\frac{1}{4})^2=20 \cdot \frac{1}{16} = 1.25f(x)=20⋅( </h2><h2>4</h2><h2>1</h2><h2> </h2><h2> ) </h2><h2>2</h2><h2> =20⋅ </h2><h2>16</h2><h2>1</h2><h2> </h2><h2> =1.25</h2><h2 /><h2>Substitute these in above formula we have;</h2><h2 /><h2>A(x) = \frac{f(2)-f(1)}{2-1}A(x)= </h2><h2>2−1</h2><h2>f(2)−f(1)</h2><h2> </h2><h2> </h2><h2 /><h2>⇒A(x) = \frac{1.25-5}{1}=-3.75A(x)= </h2><h2>1</h2><h2>1.25−5</h2><h2> </h2><h2> =−3.75</h2><h2 /><h2>therefore, average rate of change of the function f(x) from x = 1 to x = 2 is, -3.75</h2>
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The value of the directrix is -5/4.
According to the statement
we have given that the equation of parabola is y2 = 5x. And we have to find that the which equation represents the directrix.
We know that the general equation of parabola is
(y - k)2 = 4a(x - h) -(1)
and given parabola equation is
y2 = 5x. -(2)
After comparing the both equations we get k=0 and h=0
And the formula to find the directrix is
x = h - a
Substitute the values of h and a in it then
x = 0-5/4
x = -5/4.
Here the directrix is -5/4.
So, The value of the directrix is -5/4.
Learn more about the Parabola here brainly.com/question/4061870
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Answer:
9 labours
Step-by-step explanation:
In order to solve this, we must know which kind of proportionality is this. There are two types of proportions, direct and indirect/inverse proportions. In direct proportion, if one quantity increases, the other quantity also increases.
In indirect proportion, if one quantity increases, the other decreases and vice versa.
As per this question, we know if the number of labour increases, the number of days to complete a work decreases, thus proving that this is an indirect/inverse proportion.
6 labours => 12 days
x labours => 8 days
Since its an inverse proprotion, multiply 6 with 12, and x with 8.
8x = 6 × 12
x = 
∴ x = <u>9 labours</u>
First let's get rid of the parenthesis:
12 - 4x + 3x = 4 + 10 + 2x
Now group the x's on the left and the numbers on the right
-4x + 3x - 2x = 4 + 10 - 12
...and simplify
-3x = 2
divide by -3 to isolate x
x = -2/3
