Hello :
x²+8x-3=0
(x² +2(4)x +4²) -4² -3 = 0
(x+4)²-19 = 0
(x+4)² = 19
x+4 = √19 or x+4 = - √19
x = √19 - 4 or x = -√19 - 4
Answer:
Step by Step:
x-2y=4
+2y +2y
x=-2y+4
x-2y=4
-4 -4
x-2y-4=0
+2y +2y
x-4=2y
Divid by 2
1/2x-2= y
x=-2y+4
x=-2(1/2x-2)+4
x=-x+4+4
x=-x+8
+x +x
2x= 8
x=4
y=1/2x-2
y=1/2(4)-2
y=2-2
y=0
(4,0)
Using a system of equations, it is found that Gina got 22 questions correct in the test.
<h3>What is a system of equations?</h3>
A system of equations is when two or more variables are related, and equations are built to find the values of each variable.
In this problem, the variables are:
- Variable x: Number of questions she got correct.
- Variable y: Number of questions she got wrong.
The test has 30 questions, hence:
x + y = 30 -> y = 30 - x.
She scored 152 points, hence, considering the value of each question:
8x - 3y = 152.
Since y = 30 - x:
8x - 3(30 - x) = 152
11x = 242
x = 242/11
x = 22
Gina got 22 questions correct in the test.
More can be learned about a system of equations at brainly.com/question/24342899
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Answer:
NO
Step-by-step explanation:
The changeability of a sampling distribution is measured by its variance or its standard deviation. The changeability of a sampling distribution depends on three factors:
- N: The number of observations in the population.
- n: The number of observations in the sample.
- The way that the random sample is chosen.
We know the following about the sampling distribution of the mean. The mean of the sampling distribution (μ_x) is equal to the mean of the population (μ). And the standard error of the sampling distribution (σ_x) is determined by the standard deviation of the population (σ), the population size (N), and the sample size (n). That is
μ_x=p
σ_x== [ σ / sqrt(n) ] * sqrt[ (N - n ) / (N - 1) ]
In the standard error formula, the factor sqrt[ (N - n ) / (N - 1) ] is called the finite population correction. When the population size is very large relative to the sample size, the finite population correction is approximately equal to one; and the standard error formula can be approximated by:
σ_x = σ / sqrt(n).
Answer:
C. x = -12 and x = 2
Step-by-step explanation:
-x²-10x+24=0 Original equation
x²+10x-24=0 Divide everything by -1
(x+12)(x-2)=0 Factor it out
x=-12,2 Solve so that the inside of the parentheses equals 0
