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3 years ago

Someone Help me solve these by substitution please !

Mathematics

1 answer:

PSYCHO15rus [73]3 years ago

8 0

I think the answer is:

X=3

Y=-2

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How to solve this question

VMariaS [17]

The variance method is as follows.

-Sum the squares of the values in data set, and then divide by the number of values in data set
- From that, subtract the square of the mean (add all values and divide by number of values in the data set)

Our variance is

 $\displaystyle\sigma^2 = \frac{2^2 + 5^2 + m^2}{3} - \left(\frac{2 + 5 + m}{3}\right)^2$

Since variance has to be 14, we set $\sigma^2 = 14$ and solve for m

$14= \frac{4 + 25 + m^2}{3} - \left(\frac{7 + m}{3}\right)^2\ \Rightarrow \\ \\
14 = \frac{29}{3} + \frac{1}{3}m^2 - \frac{1}{9}(7+m)^2 \\ \\
14 = \frac{29}{3}+ \frac{1}{3}m^2 - \frac{1}{9}(49 + 14m + m^2) \\ \\
14 = \frac{29}{3}+ \frac{1}{3}m^2 - \frac{49}{9}- \frac{14}{9}m- \frac{1}{9}m^2 \\ \\
0 = \frac{-88}{9} -\frac{14}{9}m + \frac{2}{9}m^2
$

quadratic formula

$m = \displaystyle\frac{-b \pm \sqrt{b^2 -4ac}}{2a} \\
m = \frac{-(-\frac{14}{9}) \pm \sqrt{\left(-\frac{14}{9}\right)^2 - 4(2/9)(-88/9)} }{2(2/9)} \\
m = \frac{\frac{14}{9} \pm \sqrt{ \frac{196}{81} + \frac{704}{81} } }{\frac{4}{9} } \\
m = \frac{\frac{14}{9} \pm \sqrt{ \frac{900}{81} } }{\frac{4}{9} } \\
m = \frac{\frac{14}{9} \pm \sqrt{ \frac{100}{9} } }{\frac{4}{9} } \\
m = \frac{\frac{14}{9} \pm \frac{10}{3} }{\frac{4}{9} } \\
m = 11, -4$

-4 doesnt' work as it is not a positive integer

m = 11

5 0

3 years ago

How do I solve this problem? 0.3v = 1.35

kkurt [141]

Divide each side of the equation by 0.3 .

6 0

3 years ago

Read 2 more answers

If G(s) is the inverse of S(g) , and G(2) =16 then s(16) = 2 true or false?

lina2011 [118]

If f(x) is the inverse of g(x) then if f(a)=b then g(b)=a

so if G(s) is the inverse of S(g) then if G(2)=16 then S(16)=2, true

yes, it's true

A is answer

6 0

3 years ago

Read 2 more answers

Someone that understand this can help me out?

Kryger [21]

Plug in -2 to x in the formula
So f(-2)= ((-2)+1)^2
Your answer should be: 1

7 0

3 years ago

Solve the equation 40 = -10(y+0.3). what does the y equal

alexdok [17]

Answer:

y = -4.3

Step-by-step explanation:

40 = -10(y + 0.3) {Step 1: Use the distributive property to multiply -10 by y + 0.3}

40 = -10y + -10(0.3)

40 = -10y - 3 {Step 2: Add 3 to both sides.}

40 + 3 = -10y

43 = -10y {Step 3: Divide both sides by -10}

43/-10 = y

-4.3 = y

y equals -4.3.

4 0

3 years ago

Read 2 more answers