To get the number of standard deviation that 77 is from the mean, we get the z-score:
z-score is given by
z=(x-μ)/σ
where:
μ-mean
σ-standard deviation
thus the value of z from the information above is:
x=77
μ=58
σ=7
z=(77-58)/7=2.7143
Answer:
Step-by-step explanation:
The equation is x^4 – 5x^2 – 36 = 0
We will break the middle term:
Firstly multiply the coefficient of x^4 by constant term of the equation:
1*36 = 36
Now find any two numbers whose product is 36 and their sum or difference is equal to 5
9*4 = 36
9-4 = 5
Now,
x^4 – 5x^2 – 36 = 0
x^4-9x^2+4x^2-36=0
Now take the common:
x^2(x^2-9)+4(x^2-9)=0
(x^2+4)(x^2-9)=0
x²+4=0,
x²= 0-4,
x²=-4,
Take root on both sides:
√x²=+/-√-4
+/-√-4 = +/-√-1 *√4
√-1 = i
Then +/-√-1 *√4 = √4 i
We know that the root of 4 is 2
Then we can write it as +/-2i
Thus x = 2i , -2i
Now (x^2-9)= 0
x²=0+9
x²=9
Take square root on both sides:
√x²=√9
x=+/-3
x= 3, -3
Therefore the values of x are 2i, -2i, 3 , -3 ....
Answer:
C
Step-by-step explanation:
A counterexample for the statement 'All square roots are irrational numbers.' is the square root of 9. This is because when simplified, the answer is 3.
For a number to be irrational, it can't be expressed in fractional form. However, 3 can be expressed in fractional form as 3/1.
Answer:
x = -1
Step-by-step explanation:
2x + 5x = -7
7x = -7
x = -1
