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weeeeeb [17]
2 years ago
10

Statement 4x = 7x - 21 Reason ?

Mathematics
2 answers:
denpristay [2]2 years ago
4 0

Answer:

solution;

21=7x-4x

21=3x

21x/3x

Then finalay aneswer is 7x

bagirrra123 [75]2 years ago
3 0
4x = 7x -21
4x - 7x = -21
-3x = -21
X = 7

Check your work for your reason
4(7) = 7 (7) -21
28 = 49-21
28 = 28
They equal
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Which will result in a difference of squares? (–7x + 4)(–7x + 4) (–7x + 4)(4 – 7x) (–7x + 4)(–7x – 4) (–7x + 4)(7x – 4)
maw [93]

You can simply expand each product and see whether it gives you a difference of squares.


•  \mathsf{(-7x+4)\cdot (-7x+4)}

That's actually  \mathsf{(-7x+4)^2:}

     \mathsf{(-7x+4)^2}\\\\ \mathsf{=(-7x+4)\cdot (-7x+4)}\\\\ \mathsf{=(-7x+4)\cdot (-7x)+(-7x+4)\cdot 4}\\\\ \mathsf{=49x^2-28x-28x+16}

     \mathsf{=49x^2-56x+16}        <span>✖

which is not a difference of squares.

</span>————<span>—

</span>•  \mathsf{(-7x+4)\cdot (4-7x)}

     \mathsf{=(-7x+4)\cdot 4-(-7x+4)\cdot 7x}\\\\ \mathsf{=-28x+16-(-49x^2+28x)}\\\\ \mathsf{=-28x+16+49x^2-28x}

     \mathsf{=49x^2-56x+16}        ✖

which is not a difference of squares.

—————

•  \mathsf{(-7x+4)\cdot (-7x-4)}

     \mathsf{=(-7x+4)\cdot (-7x)-(-7x+4)\cdot 4}\\\\ \mathsf{=49x^2-28x-(-28x+16)}\\\\ \mathsf{=49x^2-\diagup\!\!\!\!\! 28x+\diagup\!\!\!\!\! 28x-16}\\\\ \mathsf{=49x^2-16}

     \mathsf{=(7x)^2-4^2}        <span>✔

That is a difference of two squares.

</span>————<span>—

</span>•  \mathsf{(-7x+4)\cdot (7x-4)}

     \mathsf{=(-7x+4)\cdot 7x-(-7x+4)\cdot 4)}\\\\ \mathsf{=-49x^2+28x-(-28x+16)}\\\\ \mathsf{=-49x^2+28x+28x-16}

     \mathsf{=-49x^2+56x-16}        <span>✖

</span>which is not a difference of squares.

—————

Only the  third option  will result in a difference of squares.


Answer:  (− 7x + 4) · (− 7x − 4).


I hope this helps. =)

8 0
3 years ago
Read 2 more answers
The pond at a local park is home to a number of birds. ⅕ of the birds are white. ⅔ of the white birds are ducks. ¾ of the ducks
vivado [14]

Answer:

Step-by-step explanation:

the park has 1/5 white birds

out of this number, 2/3 are ducks

ducks=(1/5)/(2/3)=3/10

hungry ducks=(3/10)/(3/4)=6/15

6 0
2 years ago
Given f(x) = –5x + 1, what is f(–2)?
DiKsa [7]
F(x) = -5x + 1

f(-2) = -5(-2) + 1
f(-2) = 10 + 1
f(-2) = 11

----------------------------------------------
Answer: f(-2) = 11 (Answer C)
----------------------------------------------
3 0
3 years ago
Please answer these questions I have an f if I don't get help I will die
Softa [21]

Answer:

rip just search em up and its kinda blurry sorry

Step-by-step explanation:

4 0
3 years ago
It’s due late tonight can some pls help me pass
miskamm [114]
Answer: C
The x row goes up every time by two and the y decreases by 4.
6-4=2 ect...
MARK THE BEST PLZ!!
4 0
3 years ago
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