At the city museum, child admission is
1 answer:
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Answer:
- x = ±√3, and they are actual solutions
- x = 3, but it is an extraneous solution
Step-by-step explanation:
The method often recommended for solving an equation of this sort is to multiply by the product of the denominators, then solve the resulting polynomial equation. When you do that, you get ...
... x^2(6x -18) = (2x -6)(9)
... 6x^2(x -3) -18(x -3) = 0
...6(x -3)(x^2 -3) = 0
... x = 3, x = ±√3
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Alternatively, you can subtract the right side of the equation and collect terms to get ...
... x^2/(2(x -3)) - 9/(6(x -3)) = 0
... (1/2)(x^2 -3)/(x -3) = 0
Here, the solution will be values of x that make the numerator zero:
... x = ±√3
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So, the actual solutions are x = ±3, and x = 3 is an extraneous solution. The value x=3 is actually excluded from the domain of the original equation, because the equation is undefined at that point.
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<em>Comment on the graph</em>
For the graph, we have rewritten the equation so it is of the form f(x)=0. The graphing program is able to highlight zero crossings, so this is a convenient form. When the equation is multiplied as described above, the resulting cubic has an extra zero-crossing at x=3 (blue curve). This is the extraneous solution.
Given:
The graph of a proportional relationship.
To find:
The constant of proportionality, the value of y when x is 24 and the value of x when y is 108.
Solution:
If y is directly proportional to x, then
...(i)
Where, k is the constant of proportionality.
The graph of proportional relationship passes through the point (5,15).
Substituting x=5 and y=15 in (i), we get
Therefore, the constant of proportionality is 3.
Substituting k=3 in (i) to get the equation of the proportional relationship.
...(ii)
Substituting x=24 in (ii), we get
Therefore, the value of y is 72 when x is 24.
Substituting y=108 in (ii), we get
Therefore, the value of x is 36 when y is 108.