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jekas [21]
3 years ago
8

Which of these is a correct identity? x + 4x = 5x 6x = 18 2x + 1 = 7 7x + 9 = x

Mathematics
1 answer:
dolphi86 [110]3 years ago
7 0

Answer:

x + 4x = 5x

Step-by-step explanation:

An identity is a mathematical equation that is always true (here - for all possible x's).

a). x + 4x = 5x; this is true, because for any possible x

x+4x = (1 + 4)x = 5x; there's not much to add.

b). 6x=18; evaluates to

x = 3; so it only works for one x, not all possible xs.

c). 2x + 1 = 7

2x = 6

x = 3; so it only forks for one x

d). 7x + 9 = x

6x + 9 = 0; we could compute the exact x it works for from here, but suffice to say this doesn't work for x = 0.

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PLEASE HELP ME THIS.. I REALLY NEED<br> HELP
Colt1911 [192]

9514 1404 393

Answer:

  5 hours

Step-by-step explanation:

A quick way to look at this is to compare the difference in hourly charge to the difference in 0-hour charge.

The first day, the charge is $3 more than $12 per hour.

The second day, the charge is $12 less than $15 per hour.

The difference in 0-hour charges is 3 -(-12) = 15. The difference in per-hour charges is 15 -12 = 3. The ratio of these is ...

  $15/($3/h) = 5 h

The charges are the same after 5 hours.

__

If you write equations for the charges, they will look like ...

  y1 = 15 + 12(x -1)

  y2 = 3 + 15(x -1)

Equating these charges, we have ...

  15 +12(x -1) = 3 + 15(x -1)

  12x +3 = 15x -12 . . . . . . . . eliminate parentheses

  15 = 3x . . . . . . . . . . add 12-12x

  x = 15/3 = 5 . . . . . . divide by 3

You might notice that the math here is very similar to that described in words, above.

The charges are the same after 5 hours.

6 0
3 years ago
Simplify 7 − 5(3)2 ?
Anastaziya [24]
The answer is 7 - 7.5

you multiply 5 and 3 and get 15 then divide by 2
8 0
3 years ago
Find the area and circumference of a circle with a radius of 18 meters.​
miskamm [114]

Answer:

Area: about 1017.88

Circumference: about 113.1

Step-by-step explanation:

Area Formula:A= πr^2

Circumference Formula:C=2πr

4 0
3 years ago
I need help with this please
Alexus [3.1K]

Answer:32

Step-by-step explanation:

5 0
3 years ago
Read 2 more answers
Simplify the expression. Rewrite using only positive exponents.
Dvinal [7]

The simplified form of the given expression is x^{18}a^{3}b^{3}.

The given expression is (\frac{x^{4}a^{2}b^{3} }{x^{-2}ab^{2}} )^{3}.

We need to simplify the given expression.

<h3>What are the basic laws of exponents?</h3>

The basic laws of exponents are as follows:

a^{m} \times b^{m} =(ab)^{m}

a^{m} \div b^{m} =(\frac{a}{b} )^{m}

a^{m} \times a^{n} =(a)^{m+n}

a^{m} \div a^{n} =(a)^{m-n}

Now, (\frac{x^{6}a^{2}b^{3} }{ab^{2}} )^{3}=(\frac{x^{18}a^{6}b^{9} }{a^{3}b^{6}} )

=x^{18}a^{3}b^{3}

Therefore, the simplified form of the given expression is x^{18}a^{3}b^{3}.

To learn more about the exponents visit:

brainly.com/question/26296886.

#SPJ1

4 0
1 year ago
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