Need help with math work

Mathematics

2 answers:

gizmo_the_mogwai [7]3 years ago

4 0

Plug in x = 12 and y = -5 into the given equation:-

3(12) - 3(-5) = 36 + 15 = 51 Not 21

So (12,-5) is not a solution.

frosja888 [35]3 years ago

3 0

Review: a "solution" to an equation is a numerical value (or set of values) that makes the equation true.

Here you are given the linear equation 3x - 3y = 21 and the point (12,-5). If x=12 with y= -5, then (12,5) is a solution of 3x - 3y = 21.

Substituting, 3(12) - 3(-5) = 21. Is this true or false?

36 + 15 = 21 is obviously not true. Thus, (12, -5) is NOT a solution of 3x - 3y = 21.

You might be interested in

Find the standard deviation for the set of data. (17,26,28,9,30, 29,6,21,23}

gogolik [260]

Using it's concept, the standard deviation for the given data-set is of 8.22.

<h3>What are the mean and the standard deviation of a data-set?</h3>

The mean of a data-set is given by the <u>sum of all values in the data-set, divided by the number of values</u>.

The standard deviation of a data-set is given by the square root of the <u>sum of the differences squared between each observation and the mean, divided by the number of values</u>.

The mean for this problem is:

M = (17 + 26 + 28 + 9 + 30 + 29 + 6 + 21 + 23)/9 = 21

Hence the standard deviation is:

$S = \sqrt{\frac{(17-21)^2 + (26-21)^2 + (28-21)^2 + \cdots + (21-21)^2 + (23-21)^2}{9}} = 8.22$