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2 years ago

6r+7=13+7r I don’t know what it is

Mathematics

2 answers:

Sergio [31]2 years ago

6 0

6r+7=13+7r

Move 7r to the other side. Sign changes from +7r to -7r.

6r-7r+7=13+7r-7r

6r-7r+7=13

-r+7=13

Move +r to the other side. Sign changes from +7 to -7.

-r+7-7=13-7

-r=6

Multiply by -1 to get positive and for 6

-r(-1)=6(-1)

r=-6

Answer: r=-6

PilotLPTM [1.2K]2 years ago

6 0

<h3>Answer:</h3>

$\large\boxed{r=-6}$

<h3>Step-by-step explanation:</h3>

In this question, we would be solving for r.

What this means is that we need to figure out what r is.

We would be using this equation:

$6r+7=13+7r$

We will get the r variables to one side and solve from there.

Solve:

$6r+7=13+7r\\\\\text{Subtract 7r to both sides}\\\\-r+7=13\\\\\text{Subtract 7 on both sides}\\\\-r=6\\\\\text{Divide by -1, since the variable r can't be a negative}\\\\r=-6$

When you're done solving, you should get -6.

This means that r = -6

<h3>I hope this helped you out.</h3><h3>Good luck on your academics.</h3><h3>Have a fantastic day!</h3>

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Solve the system of equations by using substitution.<br> x+8y=-2<br> x-3y=20

zysi [14]

Answer:

(14, -2)

Step-by-step explanation:

To solve by using substitution, begin by solving for a variable in the first equation. Let's solve for x:

$x+8y=-2\\x=-2-8y$

Now we know what <em>x</em> equals. Let's substitute this into the second equation:

$x-3y=20\\(-2-8y)-3y=20$

We can then simplify:

$-2-8y-3y=20$ Given equation

$-2-11y=20$ Combine y terms

$-11y=22$ Add 2

$y=-2$ Divide by -11

So, we now know the value of y = -2.

To find the value of X, we can substitute the value of Y into one of the equations. Let's use the first one:

$x+8y=-2$

$x+8(-2)=-2$ Substitute for y

$x-16=-2$ Distribute 8

$x=14$ Add 16

So, we now know the value of x = 14.

Therefore, we know a solution to the system of equations is (14, -2).

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2 years ago

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Y=x^2-3x-6<br><br>x+y=2<br><br><br>Help 50 Points!!! Show Work

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olga55 [171]

Answer:

$\text{Length of AB is }\frac{ah}{a+h}$

Step-by-step explanation:

Given △KMN, ABCD is a square where KN=a, MP⊥KN, MP=h.

we have to find the length of AB.

Let the side of square i.e AB is x units.

As ADCB is a square ⇒ ∠CDN=90°⇒∠CDP=90°

⇒ CP||MP||AB

In ΔMNP and ΔCND

∠NCD=∠NMP (∵ corresponding angles)

∠NDC=∠NPM (∵ corresponding angles)

By AA similarity rule, ΔMNP~ΔCND

Also, ΔKAP~ΔKPM by similarity rule as above.

Hence, corresponding sides are in proportion

$\frac{ND}{NP}=\frac{CD}{MP} \thinspace\thinspace and\thinspace\thinspace \frac{KA}{KP}=\frac{AB}{PM} \\\\\frac{ND}{NP}=\frac{x}{h} \thinspace\thinspace and\thinspace\thinspace \frac{KA}{KP}=\frac{x}{h}\\\\\frac{NP}{ND}=\frac{h}{x} \thinspace\thinspace and\thinspace\thinspace \frac{KP}{KA}=\frac{h}{x}\\\\\frac{PD}{ND}=\frac{h}{x}-1 \thinspace\thinspace and\thinspace\thinspace \frac{AP}{KA}=\frac{h}{x}-1\\$

$KA(\frac{h}{x}-1)=AP$

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Adding above two, we get

$(KA+ND)(\frac{h}{x}-1)=(AP+PD)$

⇒ $(KN-AD)=\frac{x}{(\frac{h}{x}-1)}$

⇒ $a-x=\frac{x}{(\frac{h}{x}-1)}$

⇒ $a-x=\frac{x^2}{h-x}$

⇒ $x^2=ah-ax-xh+x^2$

⇒ $x(h+a)=ah$

⇒ $x=\frac{ah}{a+h}$

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2 years ago

The perimeter of a rectangle is 132 feet and its area is 1080 square feet. find the dimensions

FrozenT [24]

2x + 2y=132

xy=1080

Let x=1080/y

2160/y + 2y=132
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So... x=30,36 and y=36,30. Either way, the answer is 30 by 36 or 36 by 30.

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