Lol i forgot how to do this. Sorrryyy.
Answer:
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
Step-by-step explanation:
Given
In 1990; Income= $39000
In 2010; Income= $70768
Solving (a): An equation in form of f(x) = ax + b
First, we need to determine the slope, a

Taking y as income and x as year index.
When x = 0; y = 39000
When x = 20; y = 70768
Substitute these values in the above formula



Next, is to determine the formula using:

<em>Considering :When x = 0; y = 39000, we have</em>
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<em>Make y the subject of formula</em>
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<em>Express y as a function of x</em>
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Solving (b): Income in 2005
<em>In 2005, x = 15</em>
So:
becomes


<span>6x+7=6
Subtract both sides by 7
</span>6x+7-7=6-7
6x=-1
Divide both sides by 6 to isolate x
6x/6=-1/6
x=-1/6
The length of an arc length can be calculated using the formula:
s = ra
where s is the lenght of the arc
and r is the radius of the circle
a is the central angle in radians
first converts degrees to radians
a = 60 ( pi / 180)
a = pi /3 =1.05
s = 21(1.05)
s = 22 mm is the length of the arc