For what values of $x$ is it true that $x^2 - 5x - 4 \le 10$? Express your answer in interval notation.
1 answer:
Answer:
x ∈ [-2, 7]
Step-by-step explanation:
The given equation ...
x^2 -5x -4 ≤ 10
can be rewritten as ...
x^2 -5x -14 ≤ 0
and factored as ...
(x +2)(x -7) ≤ 0
Clearly, the "or equal to" condition will be met when x=-2 and x=7. For values of x between these numbers, one factor is negative and the other is positive. Hence the product will be negative. So, numbers in that interval are the solution set.
x ∈ [-2, 7]
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The value of g^-1(-3) is the value of x that makes g(x) = -3. To find it, we can solve
.. (x +4)/(2x -5) = -3
.. x +4 = -3(2x -5)
.. 7x = 11
.. x = 11/7
The desired value is
.. (3/11)*g^-1(-3)
.. = (3/11)*(11/7)
.. = 3/7
.. (x +4)/(2x -5) = -3
.. x +4 = -3(2x -5)
.. 7x = 11
.. x = 11/7
The desired value is
.. (3/11)*g^-1(-3)
.. = (3/11)*(11/7)
.. = 3/7