Question 348273: Hello I am really stuck on this algebra word problem. Please assist me in solving this problem.
The formula N=4x^2 + 5x +1 represents the number of households, N, in thousands, in a certain city tha have a computer x years after 1990. According to the formula, in what year were there 85,000 households with computers in this city?
Thank you for your assistance in advance
Answer by texttutoring(324)   (Show Source):
You can put this solution on YOUR website! N=4x^2 + 5x +1
So they're telling you that N=85 because it says N is in thousands. You need to solve for x. Whatever number you get for x, add that to 1990 and you will find the year.
N=4x^2 + 5x +1
85=4x^2 +5x + 1
0 = 4x^2 + 5x -84
You now have a quadratic equation. You can solve this using the quadratic formula.
Where a = 4, b = 5 and c = -84
After doing the algebra for the quadratic formula (or using an online solver), you will find that there are two answers:
x = -5.25 or x = 4
Choose the positive answer, x=4, because it wouldn't make sense to be negative.
That means that there were 85,000 computers in this city in 1994.
Hope this helps!
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