Answer:c
Step-by-step explanation:
Combine the fractions on the left side:
9/(x + 2) + 2/(x - 2) = 1
9 (x - 2) / ((x + 2) (x - 2)) + 2 (x + 2) / ((x + 2) (x - 2)) = 1
(9x - 18) / ((x + 2) (x - 2)) + (2x + 4) / ((x + 2) (x - 2)) = 1
(9x - 18 + 2x + 4) / ((x + 2) (x - 2)) = 1
(11x - 14) / ((x + 2) (x - 2)) = 1
Recall the difference of squares identity,
a² - b² = (a + b) (a - b)
which lets us simplify the denominator on the left side as
(11x - 14) / (x² - 4) = 1
For any real numbers a and b, if a/b = 1, then a = b. This means
11x - 14 = x² - 4
which we can rearrange as
x² - 11x + 10 = 0
Factorize the left side:
(x - 10) (x - 1) = 0
Then
x - 10 = 0 or x - 1 = 0
x = 10 or x = 1
Answer:
Step-by-step explanation:
To find the number of inches, divide miles by 9.5.
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a) 24 miles = (24 mi)×(1 in)/(9.5 mi) = (24/9.5) in ≈ 2.526 in
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b) 24 miles + 16 miles = 40 miles = (40 mi)×(1 in)/(9.5 mi) = 40/9.5 in ≈ 4.211 in
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Comment on units conversion
I find it convenient to work units conversion problems by writing a fraction that is equal to 1 and multiplying by that to change units. My fraction has the "to" units in the numerator, and the "from" units in the denominator. That way, the unwanted units cancel when the multiplication is carried out.
The fraction is equal to 1 because the measurement in the numerator is equal to the measurement in the denominator.
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Some folks prefer proportions. If you do it that way, be sure "like" is matched with "like".
map inches/ground miles = 1/9.5 = x/24
route inches/scale inches = route miles/scale miles = x/1 = 24/9.5
Answer:
x = -7
Step-by-step explanation:
