Ax+by=c
a=(-by+c)/x
b=(-ax+c)/x
c=ax+by
x=(-by+c)/a
y=(-ax+c)/b. or y= -a/b x + c/b which is slope intercept form
Answer:
3.4
Step-by-step explanation:
Standard deviation of a population is defined as:
σ² = ∑(xᵢ − μ)² / n
The standard deviation of a sample is defined as:
s² = ∑(xᵢ − x)² / (n - 1)
It's not clear which one we have, so let's calculate both.
First, we must find the mean.
μ = (5+12+15+10+12+6+8+8) / 8
μ = 9.5
Now we find the squares of the differences:
(5-9.5)² + (12-9.5)² + (15-9.5)² + (10-9.5)² + (12-9.5)² + (6-9.5)² + (8-9.5)² + (8-9.5)²
= 80
Divide by n:
σ² = 80 / 8
σ² = 10
And take the square root:
σ = √10
σ ≈ 3.2
That's not one of the answers, so let's try the standard deviation of a sample instead of a population.
Instead of dividing by n, we'll divide by n-1:
s² = 80 / 7
And take the square root:
s = √(80/7)
s ≈ 3.4
So that must be it.
The system of linear equations represents the situation is;
x + y = 125
x + y = 1255x + 8y = 775
<h3>Simultaneous equation</h3>
Simultaneous equation is an equation in two unknown values are being solved for at the same time.
let
- number of quick washes = x
- number of premium washes = y
x + y = 125
5x + 8y = 775
From equation (1)
x = 125 - y
5x + 8y = 775
5(125 - y) + 8y = 775
625 - 5y + 8y = 775
- 5y + 8y = 775 - 625
3y = 150
y = 150/3
y = 50
x + y = 125
x + 50 = 125
x = 125 - 50
x = 75
Therefore, the number of quick washes and premium washes Monica’s school band had is 75 and 50 respectively.
Learn more about simultaneous equation:
brainly.com/question/16863577
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