Answer:
x = - 3 ± 
Step-by-step explanation:
x² + 6x + 7 = 0 ( subtract 7 from both sides )
x² + 6x = - 7
using the method of completing the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(3)x + 9 = - 7 + 9
(x + 3)² = 2 ( take square root of both sides )
x + 3 = ± ( subtract 3 from both sides )
x = - 3 ±
Answer:
y=x^28x+31
Step-by-step explanation:
(a) Average time to get to school
Average time (minutes) = Summation of the two means = mean time to walk to bus stop + mean time for the bust to get to school = 8+20 = 28 minutes
(b) Standard deviation of the whole trip to school
Standard deviation for the whole trip = Sqrt (Summation of variances)
Variance = Standard deviation ^2
Therefore,
Standard deviation for the whole trip = Sqrt (2^2+4^2) = Sqrt (20) = 4.47 minutes
(c) Probability that it will take more than 30 minutes to get to school
P(x>30) = 1-P(x=30)
Z(x=30) = (mean-30)/SD = (28-30)/4.47 ≈ -0.45
Now, P(x=30) = P(Z=-0.45) = 0.3264
Therefore,
P(X>30) = 1-P(X=30) = 1-0.3264 = 0.6736 = 67.36%
With actual average time to walk to the bus stop being 10 minutes;
(d) Average time to get to school
Actual average time to get to school = 10+20 = 30 minutes
(e) Standard deviation to get to school
Actual standard deviation = Previous standard deviation = 4.47 minutes. This is due to the fact that there are no changes with individual standard deviations.
(f) Probability that it will take more than 30 minutes to get to school
Z(x=30) = (mean - 30)/Sd = (30-30)/4.47 = 0/4.47 = 0
From Z table, P(x=30) = 0.5
And therefore, P(x>30) = 1- P(X=30) = 1- P(Z=0.0) = 1-0.5 = 0.5 = 50%
Answer:
Step-by-step explanation:
The sum of the angles is ...
x° + (x +8)° + 2x° = 180°
4x +8 = 180 . . . . . . . . . . . collect terms, divide by °
x +2 = 45 . . . . . . . . . . divide by 4
x = 43 . . . . . . . . . . subtract 2
x +8 = 51
2x = 86
The angles are 43°, 51°, 86°.
Answer:
for 9, the answer is 246.49
Step-by-step explanation:
This is area of a circle correct?
The formula is PI x radius squared.
3.14 x the radius, which is 5, squared
I am re-editing this
so sorry the answer is actually 78.54
The reason why it is 78.54 is that you need to square the radius before multiplying with PI.
