SOLUTION: Level 3: Three teachers have provided you with an equation that models their salaries in million of dollars each year. Teacher A: A(x) = 4x + 50 Teacher B: B(x) = 2x2 + 3

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Question 1030968: Level 3: Three teachers have provided you with an equation that models their salaries in million of dollars each year.
Teacher A: A(x) = 4x + 50
Teacher B: B(x) = 2x2 + 31
Teacher C: W(x) = 2x - 5

During which years does Teacher A make the most money? Between what two years?
Answer by LinnW(1048) About Me  (Show Source):
You can put this solution on YOUR website!
Teacher A: A(x) = 4x + 50
Teacher B: B(x) = 2x2 + 31
Teacher C: W(x) = 2x - 5
Teacher A will always make more than Teacher C,
So let's first see when the salary for A and B are
equal.
4x+%2B+50+=+2x%5E2+%2B+31
add -4x -50 to each side
0 = 2x^2 - 4x - 19
The quadratic formula provides the following solutions
1-sqrt%2821%2F2%29 and 1%2Bsqrt%2821%2F2%29
1-sqrt%2821%2F2%29 is negative, so the root of interest
is 1%2Bsqrt%2821%2F2%29 which is approximately 4.24
From this we can say that in year 5 Teacher A
will make more than Teacher B. This will also
be true for years beyond 5