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Juli2301 [7.4K]
2 years ago
12

How to substitute equations

Mathematics
1 answer:
skelet666 [1.2K]2 years ago
5 0
When you are substituting equations, all you are doing is plugging in variables. Lets do an example..something random but easy...
y = 2x - 3
4x + 2y = 10
So since 2x + 3 equals y we are going to plug in those numbers into the second equation.
4x + 2(2x - 3) = 10
Now we distribute
4x + 4x - 6 = 10
Combine like terms.
8x - 6 = 10
Add 6 to both sides.
8x = 16
Divide.
x = 2
And thats how you substitute equations.
I hope this helps love! :)
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Cant find the answer
dedylja [7]

Answer:

Carter family = 25 hours

Davis family = 31 hours

Step-by-step explanation:

Let's say the number of hours the Carter family used their sprinkler is x and the number of hours the Davis family used their sprinkler for is y.

So combined:

x + y = 45 hours

and we are also told that:

40x + 15y = 1300 L

So we can do simultaneous equations to solve the problem.

With some rearranging, we can figure out that:

y= 45 - x

and by substituting that into the second equation:

40x + 15 (45 -x) = 40x + 675 - 15x = 1300L

25x = 1300 - 675

25x = 625

x = 25 = hours that the Carter family used their sprinkler

and we can substitute that back into the original equation to find how many hours the Davis family used their sprinkler so:

25 + y = 56

y = 31

The Davis family used their sprinkler for 31 hours whilst the Carter family used their sprinkler for 25 hours.

7 0
1 year ago
An Eastbound train (E) traveling 95 mph and a Westbound train (W) traveling 110 mph leave the same train station at different ti
Simora [160]

Answer:

The system of linear equations that can be used to determine the time that each of the trains has been traveling is:

E + W = 4 ....... Equation 1

95 E + 110W = 400  ......Equation 2

Hence,

An Eastbound train has been travelling for =  (E) = 2.67 hours

A Westbound train has been travelling for =  (W) = 1.33 hours

Step-by-step explanation:

An Eastbound train (E) traveling 95 mph and a Westbound train (W) traveling 110 mph leave the same train station at different times. After 4 hours, they are 4 00 miles apart. Which system of linear equations can be used to determine the time that each of the trains has been traveling?

Speed = Distance/Time

Distance = Speed × Time

Let the time

An Eastbound train =  (E)

A Westbound train =  (W)

E + W = 4 hours ....... Equation 1

95mph × E + 110mph × W = 400 miles

95 E + 110W = 400 miles ......Equation 2

The system of linear equations that can be used to determine the time that each of the trains has been traveling is:

E + W = 4 ....... Equation 1

95 E + 110W = 400  ......Equation 2

E = 4 - W

We substitute 4 - W for E in Equation 2

95 (4 - W) + 110W = 400  

380 - 95W + 110W = 400

Collect like terms

95W - 110W = 400 - 380

15W = 20

W = 20/15

W = 1.3333333333 hours

≈ 1.33 hours

E = 4 - W

E = 4 - 1.33 hours

E = 2.67 hours

Therefore,

An Eastbound train has been travelling for =  (E) = 2.67 hours

A Westbound train has been travelling for =  (W) = 1.33 hours

8 0
3 years ago
What is -(2 a + 2 b) + (4 a +4 b​
Masja [62]

answer: 2a+3b

I really hope this helped

8 0
3 years ago
Read 2 more answers
Jonathan uploaded some original songs and also some pictures. alissa uploaded four times as many songs, but only uploaded twice
lesya [120]

X is the number of songs and Y the number of pics

our 2 equations will be - X+y=11 & 4x+2y=24

consider x=11-y

Lets replace x in 2:

=4(11-y) +2y=24

=44-4y+2y=24

=44-24= 4y-2y

=20= 2y

=Y=20/2

=Y=10

Lets replace y in 1

=X+10=11

=X=11-10

=X=1

To learn more about equations from the given  link

brainly.com/question/269374

#SPJ4

4 0
1 year ago
Gayle installed a rectangular section of hardwood flooring measuring 12 ft by 12 ft in her family room. She plans on increasing
icang [17]

The ansa is 256=(12+x)(12+x)

6 0
2 years ago
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