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dybincka [34]
3 years ago
10

How do you check? -5r+-3=51

Mathematics
1 answer:
Varvara68 [4.7K]3 years ago
5 0

-5r + (-3) = 51

Add 3 to both sides:

-5r = 54

Divide both sides by -5 to get r alone:

r = -10.8

To check this, plug in -10.8 into the equation: -5(-10.8) + (-3) = 51

54 + (-3) = 51

54 - 3 = 51

51 = 51

This statement is true, so the answer is correct.

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Emily predicted her car payment to be $250 each month. Her actual car payment is
Nat2105 [25]

Answer:

10%

Step-by-step explanation:

(y-x)/x*100

275-250/250*100

25/250*100 which is 10

10%.

Hope this helps!

8 0
3 years ago
Two vertical poles of heights 60 ft and 80 ft stand on level ground, with their bases 100 ft apart. A cable that is stretched fr
Andreyy89

Answer:

Step-by-step explanation:

Given

height of two Poles are 60 and 80 ft

Distance between them is 100 ft

Let x be the distance of Pole of ht 80 ft from Point of stretch

thus length of rope is given by

L=L_1+L_2

L_1=\sqrt{80^2+x^2}

L_2=\sqrt{60^2+(100-x)^2}

L=\sqrt{80^2+x^2}+\sqrt{60^2+(100-x)^2}

differentiate w.r.t x we get

\frac{\mathrm{d} L}{\mathrm{d} x}=\frac{2x}{2\sqrt{80^2+x^2}}-\frac{2\left ( 100-x\right )}{\sqrt{60^2+\left ( 100-2x\right )^2}}

Put \frac{\mathrm{d} L}{\mathrm{d} x}=0 to get minimum value

\frac{2x}{2\sqrt{80^2+x^2}}=\frac{2\left ( 100-x\right )}{\sqrt{60^2+\left ( 100-2x\right )^2}}

squaring

x^2\left ( (100-x)^2+60^2\right )=(100-x)^2(80^2+x^2)

Rearranging

28x^2-1800x+640000=0

x=\frac{400}{7}

thus L_1=98.312 ft

L_2=73.73 ft

L=172.04 ft  

7 0
3 years ago
What is the arithmetic mean of the first million odd numbers
balandron [24]
It's 1,000,000: 

<span>the sum is 1 + 3 + 5 + ... 1999999 </span>

<span>= 1 + 2 + ... + 2000000 - 2*(1 + ... + 1000000) </span>

<span>= 2000000*2000001/2 - 2*(1000000*1000001 / 2) </span>

<span>= 1000000*(2000001 - 1000001) = 1000000000000 (one million million) </span>

<span>and dividing this by one million to get the average, </span>

<span>you get one million</span>
8 0
4 years ago
Solve the system of linear equations by substitution.<br><br>−2x−5y=3<br> 3x+8y=−6
Sliva [168]
First you want to know what y or x is i chose y for this on 

so the equation i'm going to use is -2x-5y=3
i want to solve for y

-2x-5y=3
+2x        +2x

-5y=2x+3
 /-5   /-5  /-5
y=-2/5x+-3/5

Now that i solved for y we substitute our answer into the next equation to solve for x like this:

3x+8y=-6
3x+8(-2/5x+-3/5)=-6
3x+ -3.2x+-4.8=-6
-0.2x+-4.8=-6
          +4.8  +4.8
-0.2x=-1.2
/-0.2    /-0.2
x=6

After you know what x is you substitute it in for any of the equations that we started with. I picked 3x+8y=-6 to find y.

3x+8y=-6
3*6+8y=-6
18+8y=-6
-18      -18
8y=-24
/8     /8
y=-3

Since we know what x and y are we substitute it with any of the equations that we started with. i picked -2x-5y=3

-2*6-5*-3=3
-12- -15=3
3=3 
so our solution (6,-3) works 

6 0
3 years ago
In the diagram, parallel lines P and Q are cut by transversal R.
vitfil [10]

RQP X t

Step-by-step explanation:

Yey

8 0
3 years ago
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