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erastovalidia [21]
3 years ago
13

I need help with #21

Mathematics
1 answer:
maksim [4K]3 years ago
7 0

Answer: x=9

Step-by-step explanation:

(5x+7)

5 x 9 = 45

45 + 7 = 52

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Write an expression for: the product of 4 and a number. Use x as the variable. Who ever gets it correct first gets brainliest.
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X(4*1) because I’m just doing what I’m told.
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2 years ago
A chemistry teacher needs to mix a 20% salt solution with an 80% salt solution to make 20 qt of a 40% salt solution. How many qu
Svetlanka [38]

Answer:

  • 6 2/3 qt 80%
  • 13 1/3 qt 20%

Step-by-step explanation:

It is often convenient to solve a mixture problem by letting a variable represent the quantity of the higher-concentration contributor to the mix.

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We can let x represent the number of quarts of 80% solution needed. Then (20-x) is the number of quarts of 20% solution needed. The amount of salt in the final mix is ...

  0.80x +0.20(20-x) = 0.40(20)

  0.60x = 0.20(20) . . . . . . . . subtract 0.20(20) and simplify

  x = 20/3 = 6 2/3 . . . . . . . . . divide by 0.60; quarts of 80% solution

  (20 -x) = 13 1/3 . . . . . . . . . . amount of 20% solution needed

The teacher should mix 6 2/3 quarts of 80% solution with 13 1/3 quarts of 20% solution.

3 0
2 years ago
Sean answered 18 of 20 quiz questions correctly. What percent of the quiz questions did Sean answer correctly?
ozzi
The answer is 90%. You get this answer by multiplying both the numerator and denominator by 5 so 18x5=90 and 20x5=100 giving you a fraction of 90/100 and a percentage of 90%.
8 0
3 years ago
Read 2 more answers
a parallelogram has one angle that measures 55 degrees. what are the measures of the other angles in the parrelogram.
Ugo [173]

a parallelogram has four sides so all its angles add up to make 360

the angle across from the 55 would also be a 55 equaling a 110 degrees angle leaving you with 250 so your other two angles both equal 125

3 0
3 years ago
suppose you know that two angles,angle A and B,are supplementary.The measure of angle A is 5 times the measure of angle B. Find
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Angle A is 150
Angle B is 30 
Supplementary= 180, so....
Angle A + Angle B = 180
150 + 30= 180

hope this helps
3 0
3 years ago
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