Select the correct answer.

Which rational expression is equivalent to this expression?
[tex]\[ \frac{4}{z-3} \][/tex]

A. [tex]\(\frac{x-3}{x+2} \cdot \frac{x+2}{4}\)[/tex]

B. [tex]\(\frac{x+2}{x-3} \cdot \frac{4}{x+2}\)[/tex]

C. [tex]\(\frac{x+2}{x-3} \div \frac{4}{x+2}\)[/tex]

D. [tex]\(\frac{x-3}{x+2} \div \frac{4}{z+2}\)[/tex]



Answer :

Sure, let's examine each option to determine which expression is equivalent to [tex]\(\frac{4}{z-3}\)[/tex].

### Option A:
[tex]\[ \frac{x-3}{x+2} \cdot \frac{x+2}{4} \][/tex]
When we simplify this, we can cancel out [tex]\(\frac{x+2}{x+2}\)[/tex]:
[tex]\[ \frac{x-3}{x+2} \cdot \frac{x+2}{4} = \frac{(x-3) \cdot (x+2)}{(x+2) \cdot 4} = \frac{x-3}{4} \][/tex]
This is not equivalent to [tex]\(\frac{4}{z-3}\)[/tex].

### Option B:
[tex]\[ \frac{x+2}{x-3} \cdot \frac{4}{x+2} \][/tex]
When we simplify this, we can cancel out [tex]\(\frac{x+2}{x+2}\)[/tex]:
[tex]\[ \frac{x+2}{x-3} \cdot \frac{4}{x+2} = \frac{(x+2) \cdot 4}{(x-3) \cdot (x+2)} = \frac{4}{x-3} \][/tex]
This simplifies correctly to [tex]\(\frac{4}{x-3}\)[/tex], which is equivalent to [tex]\(\frac{4}{z-3}\)[/tex] if we let [tex]\(x = z\)[/tex].

### Option C:
[tex]\[ \frac{x+2}{x-3} \div \frac{4}{x+2} \][/tex]
Dividing by a fraction is equivalent to multiplying by its reciprocal:
[tex]\[ \frac{x+2}{x-3} \div \frac{4}{x+2} = \frac{x+2}{x-3} \cdot \frac{x+2}{4} = \frac{(x+2) \cdot (x+2)}{(x-3) \cdot 4} = \frac{(x+2)^2}{4(x-3)} \][/tex]
This is not equivalent to [tex]\(\frac{4}{z-3}\)[/tex].

### Option D:
[tex]\[ \frac{x-3}{x+2} \div \frac{4}{z+2} \][/tex]
Dividing by a fraction is equivalent to multiplying by its reciprocal:
[tex]\[ \frac{x-3}{x+2} \div \frac{4}{z+2} = \frac{x-3}{x+2} \cdot \frac{z+2}{4} = \frac{(x-3) \cdot (z+2)}{4(x+2)} \][/tex]
This is not equivalent to [tex]\(\frac{4}{z-3}\)[/tex].

So, upon checking all the options, the correct equivalent expression to [tex]\(\frac{4}{z-3}\)[/tex] is:

[tex]\[ \boxed{B} \][/tex]