Solve x2 + 4x − 4 = 0
2 answers:
Answer:
third option
Step-by-step explanation:
Given
x² + 4x - 4 = 0 ( add 4 to both sides )
x² + 4x = 4
Using the method of completing the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(2)x + 4 = 4 + 4, that is
(x + 2)² = 8 ( take the square root of both sides )
x + 2 = ± = ± 2
( subtract 2 from both sides )
x = - 2 ± 2
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Given:
Total number of students = 27
Students who play basketball = 7
Student who play baseball = 18
Students who play neither sports = 7
To find:
The probability the student chosen at randomly from the class plays both basketball and base ball.
Solution:
Let the following events,
A : Student plays basketball
B : Student plays baseball
U : Union set or all students.
Then according to given information,
We know that,
Now,
It means, the number of students who play both sports is 5.
The probability the student chosen at randomly from the class plays both basketball and base ball is
Therefore, the required probability is .
Answer:
There are a 25% probability that Christine fails the course.
Step-by-step explanation:
We have these following probabilities:
A 50% probability that Christine finds a tutor.
With a tutor, she has a 10% probability of failling.
A 50% probability that Christine does not find a tutor.
Without a tutor, she has a 40% probability of failing.
Probability that she fails:
10% of 50%(fail with a tutor) plus 40% of 50%(fail without a tutor). So
There are a 25% probability that Christine fails the course.