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stellarik [79]
3 years ago
12

A student solved 3/x−4=x/7 in six steps, as shown.

Mathematics
2 answers:
Rudiy273 years ago
7 0

Answer:

A. The student solved the equation correctly.

Step-by-step explanation:

We have been given a student's work to solve the equation \frac{3}{x-4}=\frac{x}{7}. We are asked to chose accurate interpretation of the student's work.

Step 1: Multiply both sides by (x-4).

\frac{3}{x-4}(x-4)=\frac{x}{7}(x-4)

3=\frac{x(x-4)}{7}

Step 2: Multiply both sides by 7.

3\times 7=\frac{x(x-4)}{7}\times 7

21=x(x-4)

Step 3: Distribute x on right ride.

21=x\cdot x-x\cdot 4

21=x^2-4x

Step 4: Subtract 21 from both sides.

21-21=x^2-4x-21

0=x^2-4x-21

Step 5: Factor by splitting the middle term.

0=x^2-7x+3x-21

0=(x-7)(x+3)

Step 6: Use zero product property.

(x-7)=0, (x+3)=0

x=7,x=-3

Since student's work is correct, therefore, option A is the correct choice.

Stolb23 [73]3 years ago
5 0

Answer:

Option A.

Step-by-step explanation:

The given equation is

\dfrac{3}{x-4}=\dfrac{x}{7}

Step 1: Multiply both sides by (x-4).

3=\dfrac{x(x-4)}{7}

Step 2: Multiply both sides by 7.

21=x(x-4)

Step 3: Using distributive property.

21=x^2-4x

Step 4: Isolate all terms on one side.

0=x^2-4x-21

Step 5: Find factors by splitting the middle term.

0=x^2-7x+3x-21

0=x(x-7)+3(x-7)

0=(x-7)(x+3)

Step 6: Using zero product property, we get

x=-3, x=7

It means student solved the equation correctly.

Therefore, the correct option is A.

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 ⇒ must find the relationship between the density, mass, and volume

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<u>Let's examine the information given:</u>

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