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Korolek [52]
2 years ago
7

If 3m = 19 - n and 2m + 5n = 30, then what is the value of m?

Mathematics
1 answer:
nexus9112 [7]2 years ago
8 0

Answer:

m=5

Step-by-step explanation:

We can solve this by using a system of equations. The easiest way to solve this is by using substitution.

3m=19-n       Subtract both sides by 19 to find n.

<u>-19  -19</u>

3m-19=-n      Divide everything by -1 to make n positive.

<u>/-1        /-1</u>

n=-3m+19

Now, we can substitute n into the second equation.

2m+5(-3m+19)=30    Substitute (-3m+19) into n.

2m-15m+95=30       Simplify.

-13m+95=30              Simplify and subtract both sides by 95.

        <u>-95 -95</u>

-13m=-65                    Divide both sides by -13.

<u>/-13    /-13</u>

m=5

We don't need to solve for n at all, so that is the answer!

Hope this helps, and have an amazing day ♥

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What is the growth rate for 3x-y=8x-7
nydimaria [60]

Answer:

you mean like this :))

-5x +7 = Y

Step-by-step explanation:

3x - y = 8x - 7

<=>3x - 8x = y - 7

<=>-5x = y - 7

<=>-5x + 7 = Y

8 0
3 years ago
Two trains are 210 miles apart, and their speeds differ by 17 mph. Find the speed of each train if they are traveling toward eac
Marizza181 [45]
V1 - velocity first train
v2 - velocity second train
v2 > v1

v2 - v1 = 17 mph

We know, that: 
s_1+s_2=210 \ [miles] \\ \\ t_1=t_2=2h

So:

v_1=\dfrac{s_1}{t_1}=\dfrac{s_1}{2} \\ \\ v_2=\dfrac{s_2}{t_2}=\dfrac{s_2}{2} \\ \\ \\ v_1+v_2= \dfrac{s_1}{2}+\dfrac{s_2}{2} \\ \\ v_1+v_2= \dfrac{s_1+s_2}{2} \\ \\  v_1+v_2= \dfrac{210}{2}=105

NOw we've got simple system of equations:

+\begin{cases} v_2-v_1=17 \\ v_2+v_1=105\end{cases} \\ \\ 2v_2=122 \qquad /:2 \\ \\ v_2=61 \qquad [mph] \\ \\ v_2-v_1=17 \\ \\ 61-v_1=17 \\ \\ v_1=44

Velocities of these trains are  61mph  and 44mph

3 0
2 years ago
Read 2 more answers
Can someone solve this? The answer needs to be in fraction form so can't be done by a calculator.
Lesechka [4]

Answer:

9 1/6

You may use a fraction calulator for this question by the way!

Hope this helps!

Sorry if its wrong!

Have a nice day!

7 0
3 years ago
What is the number below that subtracted 7 from four times it multiplied and equals 1?
Dvinal [7]

Answer:

a.4

Step-by-step explanation:

because

4 0
3 years ago
Which shows one way to determine the factors of x3 + 5x2 – 6x – 30 by grouping?
frutty [35]

Answer:

D

Step-by-step explanation:

group them first :

( x3+5x2) and ( -6x-30)

then simply by gcf ( greatest common factor) :

x2(x+5) and -6(x+5)

and just add them together:

x2(x+5)-6(x+5)

bonus :

it can be written as (x2-6)(x+5)

6 0
3 years ago
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