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Reil [10]
2 years ago
12

Use substitution to solve the system. x=3y-8 3x-4y=-9

Mathematics
2 answers:
iragen [17]2 years ago
8 0
Equation 1)  x = 3y - 8
Equation 2)  3x - 4y = -9

For equation 1, subtract 3y from both sides.

1)  x - 3y = -8

Then, multiply ALL of equation 1 by 3.

1)  3(x - 3y = -8)

1)  3x - 9y = -24
2)  3x - 4y = -9

Subtract equations from one another.

-5y = -15

Divide both sides by -5.

y = 3

Plug in 3 for y in the second equation.

3x - 4y = -9

3x - 4(3) = -9

Simplify.

3x - 12 = -9

Add 12 to both sides.

3x = -9 + 12

Simplify.

3x = 3

x = 1

~Hope I helped!~
nadya68 [22]2 years ago
5 0
<span>x=3y-8
3x-4y=-9

We are told that:
</span>x=3y-8

So replace x in 3x-4y=-9 with x=3y-8 like so: 
3(3y-8)-4y=-9 

Start by distributing the 3: 
(3)(3y)+(3)(-8)+-4y=-9
Now you have: 
9y+-24+-4y=-9&#10;
Combine like terms, now you have: 
5y-24=-9&#10;
add 24 to both sides 
5y-24+24=-9+24&#10;
Now you have:
5y=15
Divide both sides by 5 to get: 
y=3 

Now that you know y=3 plug it into: 
x=3y-8
x=3(3)-8
x=1 

Final answer: 
(1,3) 
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katie collets stamp she has stamps from canada, United Staes,ands Rest of the world in a ratio of 1:1.2:1.5 she has 135 stamps f
lyudmila [28]

Answer:

90 stamps from Canada, 108 stamps from the United States, and 135 stamps from the Rest of the World

Step-by-step explanation:

Since this is a problem of proportion we can use the Rule of three to solve this. We do this by multiplying the diagonal available values and dividing by the third value in order to get the missing variable, which in this case would be the number of stamps in the other country. Like so...

1.5  <=====>  135 stamps

1.2  <=====>  x  stamps (United States)

(1.2 * 135) / 1.5 = 108 stamps (United States)

1.5  <=====>  135 stamps

1  <=====>  x  stamps (Canada)

(1 * 135) / 1.5 = 90 stamps (Canada)

Finally, we can see that Katie had 90 stamps from Canada, 108 stamps from the United States, and 135 stamps from the Rest of the World. All creating a ratio or 1:1.2:1.5

8 0
2 years ago
Can u help me step by step need to fill in the blanks
Rina8888 [55]
-18a+17b is the answer because you multiply by -1 to each
6 0
3 years ago
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What is 245 and 7/50 in decimal form
kondaur [170]

Answer:

245=2.45

7/50=0.14

Step-by-step explanation:

divide by 100

USE MATHAWAY DOT COM!!

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Please help with these 2 questions :(( I really will appreciate it a lot
Art [367]

Answer:

c

Step-by-step explanation

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pls mark brainliest

4 0
2 years ago
<img src="https://tex.z-dn.net/?f=%5C%5C%20%5Cleq%20%5Cbeta%20%5Calpha%20%5Calpha" id="TexFormula1" title="\\ \leq \beta \alpha
nadya68 [22]
Hi lol I don’t understand you’re question I need more context
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2 years ago
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