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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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Diamonds have a density of 3.5 LaTeX: \frac{g}{cm^3}g c m 3. How big is a diamond that has a mass of 0.10 g?
liubo4ka [24]

For this case we have that by definition, the density is given by:

d = \frac {M} {V}

Where:

M: It is the mass of the diamond

V: It is the volume of the diamond

According to the data of the statement we have:

d = 3.5 \frac {g} {cm ^ 3}\\M = 0.10 \ g

So the volume is:

V = \frac {M} {d}\\V = \frac {0.10 \ g} {3.5 \frac {g} {cm ^ 3}}\\V = 0.02857\\V = 0.03 \ cm^3

Thus, the volume of the diamond is approximately 0.03 \ cm ^ 3

Answer:

0.03 \ cm ^ 3

3 0
3 years ago
Pls answer 9-12 will give brainliest
Elanso [62]
9. $112.50 / 9 lawns = $12.50 per lawn
10. $122.50 / 7 lawns = $17.50 per lawn
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Alastair earns more per hour
12. Taryn: 49 more hours ($735 / $15.00)
Alastaie: 30 more hours ($735 / $24.50)
You found how much money they charge per hour in 11 so use that to find how many hours it takes to earn $735.
6 0
3 years ago
Use the graph to answer the question.
dmitriy555 [2]

Answer:

B.

Step-by-step explanation:

hope it helps :)

3 0
3 years ago
The Martinez family walked three over five of a mile in three over eight of an hour. What equation can be used to calculate thei
jolli1 [7]
Velocity=distance/time

v=d/t

So in this case:

v=(3mi/5)/(3hr/8)  that's the equation you need to solve.

v=(3m/5)*(8/3hr)

8/5 mph=(3m/5)*(8/3hr)

1 3/5 mph= (3/5)/(3/8)

So the first statement is correct.
7 0
3 years ago
If 0.9x-1.3=-3.1, what is the value of x-0.8?
Butoxors [25]
−<span>2.8
</span>Okay so "0.9x-1.3=-3.1" x=-2
 
<span><span><span>0.9x</span>−1.3</span>=<span>−3.1

</span></span>add 1.3 to both sides

<span><span><span><span>0.9x</span>−1.3</span>+1.3</span>=<span><span>−3.1</span>+1.3

</span></span><span><span>0.9x</span>=<span>−1.8

</span></span>divide both sides by 0.9

<span><span><span>0.9x/</span>0.9</span>=<span><span>−1.8/</span><span>0.9

</span></span></span>x=<span>−2</span>

So if you plug in -2 into "x-0.8" you get −2.8

<span>=<span><span>−2</span>−0.8

</span></span><span>=<span><span>−2-</span><span>0.8

</span></span></span><span>=<span>−2.8

</span></span>Hope this helps. 
3 0
3 years ago
Read 2 more answers
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