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Leya [2.2K]
3 years ago
10

Solve the equations 3x + 5y = 21 -20x + 5y show your work

Mathematics
1 answer:
Digiron [165]3 years ago
8 0

Answer:

x=21/23

Step-by-step explanation:

Solve for x:

3x+5y=21−20x+5y

Add 20x to both sides:

3x+5y+20x=−20x+5y+21+20x

23x+5y=5y+21

Subtract 5y to both sides:

23x+5y+−5y=5y+21+−5y

23x=21

Divide both sides by 23:

x=21/23

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the perimeters of the square and the equilateral triangle are equal. Which equation represents this scenario? What is the value
sp2606 [1]

Answer:

1= 4(3x+3)=3(5x+0.5)

2= x=3.5

3= 54 units

Step-by-step explanation:

thats the correct answer trust me...follow me on ig autumn.mae06

6 0
4 years ago
Read 2 more answers
Can someone help me please
Anarel [89]

Answer:

Step-by-step explanation:

I made a table with a pretend number of years of teaching by picking a somewhat random number to start

"Clark has less seniority than Cornwall but more than Prendergast:"  I picked 3 for Clark 4 for Cornwall, and 2 for Prendergast, to start.

"Prendergast has more than Brown but less than Alexander:"  I see I'm running out of easy numbers here.  "Prendergast has more than Brown" means give Brown 1 year but this new teacher, Alexander needs a number between Clark and Prendergast.  To make room, I increased Clark and Cornwall by 1 and finished the remainder in the "Final Years" column:

<u>Teacher </u>     <u>Years</u>     <u> Final Years</u>

Clark         3               4

Cornwall         4               5

Prendergast                  2    

Brown                          1

Alexander                  3

The highest seniority teacher, Cornwall, is smart and refuses the job.  That leaves Clark, at number 2 seniority, to become the new supervisor.

6 0
2 years ago
Doug entered a canoe race. He rowed 3 1/2 miles in 1/2 hour. What is his average speed in miles per hour ?
Alex787 [66]
3 1/2 miles = 7/2 miles
1/2 hours= 30 minutes
So,
In 30 mins, travelled 7/2 miles
In 1 min, travelled 7/2 ÷ 30= 7/2× 1/30 = (7×1)/(2×30) = 7/60 miles
In 60 mins, travelled (7×60)/60 miles = 420/60 miles = 7 miles.
Hence, the speed is 7 miles per hour.
5 0
3 years ago
Read 2 more answers
PLEASE HELP! IN DESPERATE NEED! Please SHOW YOUR WORK! Thx so much! :)
choli [55]
The 1st one
y=37
x=18.5
7 0
3 years ago
Four times the sum of a number and 15 is at least 120. Find all possible solutions for x
zloy xaker [14]
First translate the English phrase "Four times the sum of a number and 15 is at least 120" into a mathematical inequality.

"Four times..." means we're multiplying something by 4.

"... the sum of a number and 15..." means we're adding an unknown and 15 and then multiplying the result by 4.

"... is at least 120" means when we substitute the unknown for a value, in order for that value to be in the solution set, it can only be less than or equal to 120.

So, the resulting inequality is 4(x + 15) ≤ 120.

Simplify the inequality.

4(x + 15) ≤ 120
4x + 60 ≤ 120 <-- Using the distributive property
4x ≤ 60 <-- Subtract both sides by 60
x ≤ 15 <-- Divide both sides by 4

Now that we have the inequality in a simplified form, we can easily see that in order to be in the solution set, the variable x can be no bigger than 15.

In interval notation it would look something like this:

[15, ∞)

In set builder notation it would look something like this:

{x | x ∈ R, x ≤ 15}

It is read as "the set of all x, such that x is a member of the real numbers and x is less than or equal to 15".
7 0
3 years ago
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