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3 years ago

Question 18.

Mathematics

1 answer:

DENIUS [597]3 years ago

3 0

Answer: c

Step-by-step explanation:

sampling variability is the difference between the measured value of the random sample and the mean age of the population

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It’s late work and I’ve forgotten how to do it

Veseljchak [2.6K]

You want to eliminate one of the terms (x or y) in one of the equations so you can solve for the other variable. You have to multiply by the opposite number of the coefficient to be able to eliminate the term in the other equation. If the x coefficient is 2, then you have to multiply the entire other equation by -2. If the y coefficient is -5, then you have to multiply the entire other equation by 5.

10)
-4x + 9y= 9
x - 3y= -6

STEP 1:
multiply the bottom equation by 4
4(x- 3y)= 4(-6)
4x - 12y= -24

STEP 2:
add the top equation and the equation from step 2

-4x + 9y= 9
4x - 12y= -24
the x term cancels out

-3y= 15
divide both sides by -3

y= -5

STEP 2:
substitute the y value in either original equation to solve for x

x - 3y= -6
x - 3(-5)= -6

x + 15= -6
subtract 15 from both sides

x= -21

ANSWER: x= -21; y= -5
____________________

12)
-7x + y= -19
-2x + 3y= -19

STEP 1:
multiply the top equation by -3 to eliminate the y term and to solve for x

-3(-7x + y)= -3(-19)
21x - 3y= 57

STEP 2:
add the bottom equation and the equation from step 2 to solve for x

-2x + 3y= -19
21x - 3y= 57
the y term cancels out

19x= 38
divide both sides by 19

x= 2

STEP 3:
substitute the x value in step 2 to solve for y; you can use either original equation

-7x + y= -19
-7(2) + y= -19

-14 + y= -19
add 14 to both sides

y= -5

ANSWER: x= 2; y=-5

Hope this helps! :)

4 0

3 years ago

Trigonometric functions

givi [52]

Answer:

udg7838jsj

Step-by-step explanation:

888888888888 9283

3 0

3 years ago

Read 2 more answers

Helpp!!<br> Simplify : [( 4 1/6 + 2 1/3 ) ÷ 4 1/3 ] - 1 1/2

Nadusha1986 [10]

Answer:

$\boxed{ \bold{ \huge{ \boxed{ \sf{0}}}}}$

Step-by-step explanation:

$\sf{ [ (4 \frac{1}{6} + 2 \frac{1}{3} ) \div 4 \frac{1}{3}] - 1\frac{1}{2} }$

Convert the mixed numbers into improper fraction

$\longrightarrow{ \sf{ [ ( \frac{25}{6} + \frac{7}{3} ) \div \frac{13}{3}] - \frac{3}{2}}}$

Add the fractions : 25 / 6 and 7 / 3

While performing addition or subtraction of unlike fractions, you have to express the given fractions into equivalent fractions of common denominator and add or subtract as we do with like fraction.

To do so, first take the L.C.M of 6 and 3 which results to 6

$\longrightarrow\sf{ [( \frac{25 + 7 \times 2}{6} ) \div \frac{13}{3} ] - \frac{3}{2}}$

$\longrightarrow{ \sf{ [( \frac{25 + 14}{6} ) \div \frac{13}{3} ] - \frac{3}{2} }}$

$\longrightarrow{ \sf{ [ \frac{39}{6} \div \frac{13}{3}] - \frac{3}{2} }}$

Multiply the dividend by the reciprocal of the divisor.

Reciprocal of any number or fraction can be obtained by interchanging the position of numerator and denominator

$\longrightarrow{ \sf{ [ \frac{39}{6} \times \frac{3}{13} ] - \frac{3}{2}}}$

To multiply one fraction by another, multiply the numerators for the numerator and multiply the denominators for its denominator and reduce the fraction obtained after multiplication into lowest term

$\longrightarrow{ \sf{ [ \frac{39 \times 3}{6 \times 13} ] - \frac{3}{2}}}$

$\longrightarrow{ \sf{ [ \frac{117}{78} ] - \frac{3}{2} }}$

$\longrightarrow{ \sf{ \frac{3}{2} - \frac{3}{2} }}$

While performing the addition or subtraction of like fractions , you just have to add or subtract the numerator respectively in which the denominator is retained same

$\longrightarrow{ \sf{ \frac{3 - 3}{2} }}$

Subtract 3 from 3

$\longrightarrow{ \sf{ \frac{0}{2}}}$

Divide 0 by 2

$\longrightarrow{ \sf{0}}$

Hope I helped!

Best regards!

3 0

3 years ago

Charlie runs laps around a track. the table shows how long it takes him to run different numbers of laps. how long will it take

WARRIOR [948]

Answer:

20 (minutes)

Step-by-step explanation:

Look at the first columns, and it tells us that Charlie runs 2 laps in 8 minutes. Then simply divide by two, then you'll get that Charlie runs 1 lap in 4 minutes. So for five laps, multiply 4 by 5, which is 20.

3 0

3 years ago

Read 2 more answers

What is the measure in degrees of an angle that is supplementary to a 74° angle?

neonofarm [45]

Answer:

106°

Step-by-step explanation:

Supplementary angles total 180°, so the one supplementary to 74° is ...

180° -74° = 106°

8 0

3 years ago