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3 years ago

Which equation shows the substitution method being used to solv the system of equations?

Mathematics

1 answer:

slava [35]3 years ago

8 0

The x value in the second equation (y+2) is substituted for the x in the first equation in...

Answer A.

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A professor has recorded exam grades for 10 students in his class, but one of the grades is no longer readable. If the mean sco

Nostrana [21]

Answer:

unreadable score = 35

Step-by-step explanation:

We are trying to find the score of one exam that is no longer readable, let's give that score the name "x". we can also give the addition of the rest of 9 readable s scores the letter "R".

There are two things we know, and for which we are going to create equations containing the unknowns "x", and "R":

1) The mean score of ALL exams (including the unreadable one) is 80

so the equation to represent this statement is:

mean of ALL exams = 80

By writing the mean of ALL scores (as the total of all scores added including "x") we can re-write the equation as:

$\frac{R+x}{10} =80$

since the mean is the addition of all values divided the total number of exams.

in a similar way we can write what the mean of just the readable exams is:

$\frac{R}{9} = 85\\$ (notice that this time we don't include the grade x in the addition, and we divide by 9 instead of 10 because only 9 exams are being considered for this mean.

Based on the equation above, we can find what "R" is by multiplying both sides by 9:

$\frac{R}{9} = 85\\R=85*9= 765$

Therefore we can now use this value of R in the very first equation we created, and solve for "x":

$\frac{R+x}{10} =80\\\frac{765+x}{10} =80\\765+x=80*10=800\\765+x=800\\x=800-765=35$

4 0

3 years ago

Combine like terms 18x-(-7x)+31-(-37)-5x

viktelen [127]

Answer:

20x+68

Step-by-step explanation:

6 0

2 years ago

PLEASE HELP ME?! BRAINLIEST ANSWER PLUS EXTRA POINTS! The perimeter of a basketball court is 84 meters and he length is 6 meters

Marina86 [1]

Answer:

I hope this helps you and you have an amazing day the answer

Width=12

Length=30

Step-by-step explanation:

L=2W+6 is

P=2L+2W

84=2(2W+6)+2W

84=4W+12+2W

84=6W+12

6W=84-12

6W=72

W=72/6

W=12 ans. for the width.

L=2*12+6=24+6=30 ans. for the length.

Proof:

84=2*30+2*12

84=60+24

84=84

3 0

3 years ago

Read 2 more answers

Give an example of this when adding two rationalnumbers with different signs and provide the product.

kolezko [41]

ANSWER:

$\begin{gathered} \frac{4}{5}+-\frac{8}{3}=-\frac{28}{15} \\ \frac{4}{5}\cdot-\frac{8}{3}=-\frac{32}{15} \end{gathered}$

STEP-BY-STEP EXPLANATION:

Rational numbers are all numbers that can be expressed as a fraction, that is, as the quotient of two whole numbers.

Therefore, an example would be:

$\begin{gathered} \frac{4}{5}\text{ and - }\frac{8}{3} \\ \text{adding} \\ \frac{4}{5}+-\frac{8}{3}=\frac{4}{5}-\frac{8}{3} \\ \frac{4}{5}-\frac{8}{3}=\frac{4\cdot3-5\cdot8}{5\cdot3}=\frac{12-40}{15}=-\frac{28}{15} \\ \text{ product} \\ \frac{4}{5}\cdot-\frac{8}{3}=-\frac{4\cdot8}{5\cdot3}=-\frac{32}{15} \end{gathered}$

5 0

1 year ago

46 meters use pie= 3.14

Ugo [173]

Could you explain what you need help with for this question more? i can help i just need an explanation of what you need:)

3 0

3 years ago