Find the value of x. A B X 6 3 2 D x = [?] C
1 answer:
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Answer:
(- 3, 37) and (- ,
)
Step-by-step explanation:
Given the 2 equations
2x² - y + 19 = 0 → (1)
y + 11x = 4 → (2) ← subtract 11x from both sides
y = 4 - 11x → (3)
Substitute y = 4 - 11x into (1)
2x² - (4 - 11x) + 19 = 0
2x² - 4 + 11x + 19 = 0
2x² + 11x + 15 = 0 ← in standard form
(2x + 5)(x + 3) = 0 ← in factored form
Equate each factor to zero and solve for x
2x + 5 = 0 ⇒ 2x = - 5 ⇒ x = -
x + 3 = 0 ⇒ x = - 3
Substitute these values into (3) for corresponding values of y
x = - : y = 4 +
=
⇒ (-
,
)
x = - 3 : y = 4 + 33 = 37 ⇒ (- 3, 37 )
The z-score of the speed value gives the measure of dispersion of the from
the mean observed speed.
The probability that the speed of a car is between 63 km/h and 75 km/h is
<u>0.273</u>.
The given parameters are;
The mean of the speed of cars on the highway, = 60 km/h
The standard deviation of the cars on the highway, σ = 5 km/h
Required:
The probability that the speed of a car is between 63 km/h and 75 km/h
Solution;
The z-score for a speed of 63 km/h is given as follows;
Which gives;
From the z-score table, we have;
P(x < 63) = 0.7257
The z-score for a speed of 75 km/h is given as follows;
Which gives, P(x < 75) = 0.9987
The probability that the speed of a car is between 63 km/h and 75 km/h is therefore;
P(63 < x < 75) = P(x < 75) - P(x < 63) = 0.9987 - 0.7257 = 0.273
The probability that the speed of a car is between 63 km/h and 75 km/h is
<u>0.273</u>.
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