Question
Which of these differences yields a rational expression? A. (3x^3+2x-7)/(sqrt (x)+3)-(4x^3-3)/(2sqrt (x)-7) B. (3sqrt [3](x)+2sqrt (x)-7)/(x+3)-(4sqrt [3](x)-3)/(2x-7) C. (3x^3+2x-7)/(x+3)-(4x^3-3)/(2x-7) D. (3x^frac (1)/(3)+2x^(1)/(2)-7)(x^(1)/(2)+3)-(4x^frac (1)/(3)-3)(2x^(1)/(2)-7)
Answer
4.6
(338 Votes)
Mitchell
Elite · Tutor for 8 years
Answer
'C'
Explanation
## Step 1A rational expression is defined as the ratio of two polynomials. Each option must be analyzed to determine if it fits this definition:## Step 2 Option A: \((3x^3+2x-7)/(\sqrt{x}+3)-(4x^3-3)/(2\sqrt{x}-7)\)### The denominators
and
are not polynomials because they contain square roots of
. Therefore, this expression is not a rational expression.## Step 3 Option B: \((33\sqrt{x}+2\sqrt{x}-7)/(x+3)-(43\sqrt{x}-3)/(2x-7)\)### Similar to Option A, this expression contains square roots in the numerators, making it not a rational expression.## Step 4 Option C: \((3x^3+2x-7)/(x+3)-(4x^3-3)/(2x-7)\)### Both the numerators and denominators are polynomials. This expression is a rational expression.## Step 5 Option D: \((3x^{1/3}+2x^{1/2}-7)/(x^{1/2}+3)-(4x^{1/3}-3)/(2x^{1/2}-7)\)### This expression contains fractional powers of
in both the numerators and denominators, which do not constitute polynomials. Therefore, this is not a rational expression.Thus, the only option that yields a rational expression is Option C.