1. **State the problem:** We are given the volume function of a box as $$V(x) = 4x^3 - 130x^2 + 1000x$$ and need to show that when $x=1$, the volume is 874 cm³.
2. **Verify volume at $x=1$:** Substitute $x=1$ into the volume function:
$$V(1) = 4(1)^3 - 130(1)^2 + 1000(1)$$
$$= 4 - 130 + 1000$$
$$= 874$$
This confirms the volume is 874 cm³ when $x=1$.
3. **Find other values of $x$ for volume 874:** Solve the equation:
$$4x^3 - 130x^2 + 1000x = 874$$
Rewrite as:
$$4x^3 - 130x^2 + 1000x - 874 = 0$$
4. **Use the fact that $x=1$ is a root:** Since $x=1$ satisfies the equation, $(x-1)$ is a factor. Perform polynomial division or factor out $(x-1)$:
Divide:
$$4x^3 - 130x^2 + 1000x - 874 \div (x-1)$$
Using synthetic division:
Coefficients: 4, -130, 1000, -874
Bring down 4.
Multiply 4*1=4; add to -130: -126.
Multiply -126*1=-126; add to 1000: 874.
Multiply 874*1=874; add to -874: 0.
So quotient is:
$$4x^2 - 126x + 874$$
5. **Solve quadratic:**
$$4x^2 - 126x + 874 = 0$$
Use quadratic formula:
$$x = \frac{126 \pm \sqrt{(-126)^2 - 4 \cdot 4 \cdot 874}}{2 \cdot 4}$$
Calculate discriminant:
$$126^2 = 15876$$
$$4 \cdot 4 \cdot 874 = 13984$$
$$\sqrt{15876 - 13984} = \sqrt{1892}$$
6. **Simplify and find roots:**
$$x = \frac{126 \pm \sqrt{1892}}{8}$$
Approximate:
$$\sqrt{1892} \approx 43.5$$
So,
$$x_1 = \frac{126 + 43.5}{8} = \frac{169.5}{8} = 21.1875$$
$$x_2 = \frac{126 - 43.5}{8} = \frac{82.5}{8} = 10.3125$$
7. **Final answer:** The values of $x$ that give a volume of 874 cm³ are:
$$x = 1, 10.3125, 21.1875$$
Volume Values 03638D
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