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pav-90 [236]
3 years ago
11

Which could be the first step in solving this system of equations by substitution?

Mathematics
1 answer:
Ainat [17]3 years ago
3 0

Answer:

The first step is to replace the y in y-x=15 with 7x (we can do this because the first equation tells us that they're equal)

solve and get

(2.5,17.5)

or x= 2.5 y=17.5

Step-by-step explanation:

The first step is to recognize that y=7x which means that we can just replace the y in the second equation with 7x

7x-x=15

6x=15

x=2.5

Then we can solve for y

y=7(2.5)

y=17.5

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One half liter of lemonade concentrate is added to 3 liters of water. how many one thirds liter servings of lemonade are made.
uysha [10]
So, 3 liters of water, add 1/2 liter of lemonade, that's 3 and 1/2 liters of lemonade.

so in short, how  many times does 1/3 go into 3 and 1/2?

let's change the mixed to "improper" and divide then.

\bf \stackrel{mixed}{3\frac{1}{2}}\implies \cfrac{3\cdot 2+1}{2}\implies \stackrel{improper}{\cfrac{7}{2}}\\\\
-------------------------------\\\\
\cfrac{\quad \frac{7}{2}\quad }{\frac{1}{3}}\implies \cfrac{7}{2}\cdot \cfrac{3}{1}\implies \cfrac{21}{2}\implies 10\frac{1}{2}
8 0
3 years ago
A shopkeeper with a basket of eggs finds that if he sells 3 eggs at a time there is only one egg left if he sells four eggs at a
Agata [3.3K]

Answer:

Step-by-step explanation:

add a picture of the question please

7 0
3 years ago
Read 2 more answers
Can someone help me with 7 1/2 ÷ 1 9/10 please and thank you
Evgen [1.6K]
7 1/2÷ 1 9/10 = 15/2 ÷19/10 = 15/2x10/19 = 159/38 = 4 7/38


4 7/38 (Answer)
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38 )159
152
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4 0
3 years ago
Read 2 more answers
Can I get some help please?
IrinaK [193]

Answer: A

Step-by-step explanation:

A linear function is described as:

https://tex.z-dn.net/?f=f(x)%20%3D%20ax%20%2B%20b

When the value of x = 0, then you're left with

https://tex.z-dn.net/?f=f(x)%20%3D%20b

In this question, the speed of sound is the linear function while the temperature is the independent variable. When T = 0, you're left with

https://tex.z-dn.net/?f=S(0)%20%3D%20331.4

Which means the speed of sound in air when temperature is 0°C is 331.4m/s.

5 0
3 years ago
Read 2 more answers
A bag contains 6 red marbles, 10 white marbles, and 7 blue marbles. You draw 4 marbles out at random, without replacement. What
Lapatulllka [165]

Answer:

3/1771

Step-by-step explanation:

Probability is the chance or likelihood that an event will occur.

Probability = expected outcome/total outcome

Total outcome = total number of marbles

Total outcome = 6+7+10 = 23marbles

If four marbles are drawn, the probability that they are all red is expressed as;

Pr(picking the first red marble) = 6/23

Since it is without replacement, the total marble becomes 22

Pr(picking the second) = 5/22

Pr(picking the third marbles = 4/21

Pr(picking the 4th marble) = 3/20

Note that the number of red marbles keep reducing and the total marble keep reducing as well.

Pr(picking the 4marbles) = 6/23×5/22×4/21×3/20 (we multiplied because or is an independent events)

Pr(picking the 4marbles) = 360/212520

Pr(picking 4 red marbles) = 72/42504 =36/21,252

= 9/5313

= 3/1771

Hence the probability of picking 4 marbles at random without replacement is 3/1771

4 0
3 years ago
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