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


Answer:
Step-by-step explanation:
Combine like terms
7x^6
2x^5+5x^5= 7x^5
8x^3
-3x^2-6x^2= -9x^2
9x+2x= 11x
-5
Put back into order
7x^6+7x^5+8x^3-9x^2+11x-5