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Setler [38]
2 years ago
8

What is the elimination of 20x+5y=120 and 10x+7.5=80

Mathematics
1 answer:
Grace [21]2 years ago
5 0
20x+5y=120
10x+7.5y=80    multiply this one by 2
___________

20x+5y=120
20x+15y=160   subtract 

___________

        -10y=-40    divide both sides by -10 
____________

             y=4         

20x+5(4)=120   plug 4 in for y in the first equation 
20x+20=120     multiply 
20x=100           subtract 
x=5                   divide to find x




 
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The physician tells a woman who usually drinks 5 cups of coffee daily to cut down on her coffee consumption by 75%. If this woma
Maru [420]

Answer:

Step-by-step explanation:

5 cups per day.....1 cup = 8oz.....so 5 cups = (5 * 8) = 40 oz

cut down by 75%....means ur only drinking 25%

25% of 40 oz =

0.25(40) = 10 oz per day <===

6 0
2 years ago
A triangle is rotated 90° about the orgin. Which rule describes the transformation
Katen [24]

Step-by-step explanation:

If a triangle is rotated 90° about the origin.

The rule that describes the transformation is

(x, y) → (–y, x)

8 0
2 years ago
A square has a perimeter of 12x + 52 units. Which expression represents the side length of the square in units?
Xelga [282]

Answer:

Option (3) is correct.

side length of square is (3x + 13 ) units.

Step-by-step explanation:

For a square with side 'a'. Perimeter is defined as the sum of length of side. Since, Square has four sides. Thus Perimeter of square = 4 × side

Given square has perimeter = 12x + 52

Comparing both sides,

4 × side = 12 x +  52

⇒ Side = \frac{12x+52}{4}

⇒ Side = \frac{4(3x+13)}{4}

⇒ Side = 3x + 13

Thus, side length of square is (3x + 13 ) units.

Thus, option (3) is correct.

3 0
2 years ago
Read 2 more answers
Jayden has some dimes and some quarters. He has at most 25 coins worth at least $4.60 combined. If Jayden has 7 dimes, determine
Y_Kistochka [10]

Answer:

Step-by-step explanation:

A dime is worth 10 cents. Converting to dollars, it becomes 10/100 = $0.1

A quarter is worth 25 cents. Converting to dollars, it becomes 25/100 = $0.25

Let x represent the number of dimes that Jayden has.

Let y represent the number of quarters that Jayden has.

Jayden has some dimes and some quarters. He has at most 25 coins. It means that

x + y ≤ 25

The coins worth at least $4.60 combined. It means that

0.1x + 0.25y ≥ 4.6 - - - - - - - - - - 1

If Jayden has 7 dimes, then

7 + y ≤ 25

y ≤ 25 - 7

y ≤ 18

Substituting x = 7 into equation 1, it becomes

0.1 × 7 + 0.25y ≥ 4.6

0.7 + 0.25y ≥ 4.6

0.25y ≥ 4.6 - 0.7

0.25y ≥ 3.9

y ≥ 3.9/0.25

y ≥ 15.6

All possible values for the number of quarters that he could have would be

15.6 ≤ y ≤ 18

6 0
1 year ago
−15x+4≤109 OR −6x+70&gt;−2
Xelga [282]

-15x+4\leq109\qquad\text{subtract 4 from both sides}\\\\-15x\leq105\qquad\text{change the signs}\\\\15x\geq-105\qquad\text{divide both sides by 15}\\\\\boxed{x\geq-7}\\or\\-6x+70>-2\qquad\text{subtract 70 from both sides}\\\\-6x>-72\qquad\text{change the signs}\\\\6x

3 0
1 year ago
Read 2 more answers
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