Math Please Solve this question
Algebra

Tutor: None Selected  Time limit: 1 Day 
a) You have to find a linear function that fits the data, namely that equal 291 when x = 5 (because in 2005, 5 years after 2000 contributions was 291 mln.) and equal 396.1 when x = 7 (because in 2007, 7 years after 2000 contributions was 396.1 mln.).
Linear function always looks like y = a*x + b. Our goal now is to find parameters "a" an "b".
We know that when x = 5, y = 291. We should put it in our function. That gives us equation :
291 = a*5 + b. (1)
Similarly we can get an equation from the information that when x = 7, y = 396.1 :
396.1 = a*7 + b. (2)
Now we can subtract equation (1) from equation (2), by subtracting both sides of equations:
396.1  291 = a*7+b  (a*5 + b) = a*7+b  a*5  b.
Now we can simplify both sides :
105.1 = a*2.
And devide it on 2 to get parameter "a" :
a = 105.1 / 2 = 52.55.
Then we can put it into equation (1) to get the value of "b" :
291 =a*5 + b = (52.55)*5 + b = 262.75 + b.
Hence
b = 291  265.75 = 28.25
By putting this parameters into general linear equation y = a*x + b we get an answer:
y = 52.55 * x + 28.25
b) You have to use that function for prediction of contribution in 2010.
Namely you have to find "y", when x = 10 (2010 is 10 years later 2000) :
y = 52.55*x + 28.25 = 525.5 + 28.25 = 553.75.
And that is your answer (in millions) :
y = 553.75
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