Exponent Expression 73Ed11
1. **Stating the problem:** Simplify the expression $$- x^{\frac{2}{3}} + x^{\frac{1}{3}}$$ and identify which of the given options it equals.
2. **Recall the properties of exponents:**
- $x^{a} \cdot x^{b} = x^{a+b}$
- $x^{\frac{1}{3}}$ means the cube root of $x$, i.e., $\sqrt[3]{x}$
3. **Rewrite the expression:**
$$- x^{\frac{2}{3}} + x^{\frac{1}{3}} = - (x^{\frac{1}{3}})^2 + x^{\frac{1}{3}}$$
4. **Let $y = x^{\frac{1}{3}}$ (cube root of $x$), then the expression becomes:**
$$- y^2 + y = y - y^2$$
5. **This expression is not equal to any single power of $x$ directly, but we can factor it:**
$$y - y^2 = y(1 - y) = x^{\frac{1}{3}} (1 - x^{\frac{1}{3}})$$
6. **Among the options:**
- a. $x$
- b. $x^2$
- c. $x^3$
- d. $x^{\frac{3}{2}}$
- e. $\sqrt[3]{x}$
The expression is closest to $x^{\frac{1}{3}}$ but with an additional factor $(1 - x^{\frac{1}{3}})$, so it does not equal any single option exactly.
**Final answer:** None of the options exactly equal the expression $- x^{\frac{2}{3}} + x^{\frac{1}{3}}$.
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**Example:**
If $x=8$, then:
- $x^{\frac{1}{3}} = 2$
- $x^{\frac{2}{3}} = (x^{\frac{1}{3}})^2 = 2^2 = 4$
So,
$$- x^{\frac{2}{3}} + x^{\frac{1}{3}} = -4 + 2 = -2$$
This is not equal to any of the options evaluated at $x=8$.