Answer:
8.1
Step-by-step explanation:
2x^2 -9 = 121
+9 +9
2x^2 = 130
/2 /2
x^2 = 65
x= sqrt (65)
x= 8.06225...
x = 8.1
Hey there!
The main concept of pre-algebra is solving equations for variables in them.
For example, let's say you have the algebraic equation below.
x+1=3
With algebra, you need to figure what x is equal to. To do so, you will use inverse operations on both sides of the equation to isolate x one side, showing what it is equal to.
We would subtract 1 to both sides to isolate x on one side.
x+1-1=3-1
As you can see, +1-1=0, therefore, this would give us x+0, or just x. Now it is isolated and will show us what it is equal to.
x=3-1
x=2
Therefore, in our equation x+1=3, x would be equal to 2.
I hope this explanation helps! Have a great time here at Brainly!
Adding (or subtracting) a constant to every data value adds (or subtracts) the same constant to measures of position such as center,percentiles, max or min.
Its shape and spread such as range, IQR, standard deviation remain unchanged.
When we multiply (or divide) all the data values by any constant, all measures of position (such as the mean, median, and percentiles) and measures of spread (such as the range, the IQR, and the standard deviation) are multiplied (or divided) by that same constant.
Part A:
The lowest score is a measure of location, so both addition and multiplying the lowest score of test B by 40 and adding 50 to the result will affect the lowest score of test A.
Thus, the lowest score of test A is given by 40(21) + 50 = 890
Therefore, the lowest score of test A is 890.
Part B:
The mean score is a measure of location, so both
addition and multiplying the mean score of test B by 40 and adding 50
to the result will affect the lowest score of test A.
Thus, the mean score of test A is given by 40(29) + 50 = 1,210
Therefore, the mean score of test A is 890.
Part C:
The standard deviation is a measure of spread, so multiplying the standard deviation of test B by 40 will affect the standard deviation but adding 50
to the result will not affect the standard deviation of test A.
Thus, the standard deviation of test A is given by 40(2) = 80
Therefore, the standard deviation of test A is 80.
Part D
The Q3 score is a measure of location, so both
addition and multiplying the Q3 score of test B by 40 and adding 50
to the result will affect the Q3 score of test A.
Thus, the Q3 score of test A is given by 40(28) + 50 = 1,170
Therefore, the Q3 score of test a is 1,170.
Part E:
The median score is a measure of location, so both
addition and multiplying the median score of test B by 40 and adding 50
to the result will affect the median score of test A.
Thus, the median score of test A is given by 40(26) + 50 = 1,090
Therefore, the median score of test A is 1,090.
Part F:
The IQR is a measure of spread, so multiplying the IQR of test B by 40 will affect the IQR but adding 50
to the result will not affect the IQR of test A.
Thus, the IQR of test A is given by 40(6) = 240
Therefore, the IQR of test A is 240.
