Equations Polynomials Triangle
1. Solve the equation $6x+2=24$.
Step 1: Subtract 2 from both sides: $$6x=24-2$$
Step 2: Simplify the right side: $$6x=22$$
Step 3: Divide both sides by 6: $$x=\frac{22}{6}=\frac{11}{3}$$
Answer: $x=\frac{11}{3}$.
2. Write the formula for total surface area of a cone and explain terms.
The total surface area $$A$$ of a cone is given by:
$$A=\pi r^2 + \pi rl$$
Where:
- $r$ is the radius of the base of the cone,
- $l$ is the slant height of the cone (the distance from the base edge to the apex along the side),
- $\pi$ is approximately 3.1416.
The first term $\pi r^2$ is the area of the circular base.
The second term $\pi rl$ is the lateral surface area (the side surface).
3. Check if $x^3 + x^2 - (2 + \sqrt{2})x - \sqrt{2}$ is divisible by $x + x - 2$ or not.
Note: $x+x-2=2x-2=2(x-1)$. We consider divisibility by $x-1$ (ignoring constant factor 2).
Use Polynomial Remainder Theorem for $x-1$:
Substitute $x=1$ into the polynomial:
$$1^3 + 1^2 - (2+\sqrt{2})(1) - \sqrt{2} = 1 + 1 - 2 - \sqrt{2} - \sqrt{2} = 2 - 2 - 2\sqrt{2} = -2\sqrt{2} \neq 0$$
Since remainder is not zero, the polynomial is not divisible by $x-1$, hence not divisible by $x+x-2$.
4. Find $p(-1)$, $p(0)$, $p(2)$ for $p(x) = x^3 - 2x^2 - 3$, then find mean.
Calculate:
$p(-1) = (-1)^3 - 2(-1)^2 - 3 = -1 - 2 - 3 = -6$
$p(0) = 0 - 0 - 3 = -3$
$p(2) = 8 - 8 - 3 = -3$
Mean = $\frac{-6 + (-3) + (-3)}{3} = \frac{-12}{3} = -4$
5. Find the three angles of a triangle given as $(2x)^\circ$, $(3x+10)^\circ$, and $(5x-20)^\circ$.
Sum of angles in triangle: $$2x + 3x + 10 + 5x - 20 = 180$$
Simplify:
$$ (2x + 3x + 5x) + (10 - 20) = 180 $$
$$ 10x - 10 = 180 $$
Add 10 to both sides:
$$ 10x = 190 $$
Divide by 10:
$$ x = 19 $$
Find each angle:
$$ 2x = 2 \times 19 = 38^\circ $$
$$ 3x + 10 = 3 \times 19 + 10 = 57 + 10 = 67^\circ $$
$$ 5x - 20 = 5 \times 19 - 20 = 95 - 20 = 75^\circ $$
Check sum: $38 + 67 + 75 = 180^\circ$ (valid).
Final answers:
1. $x=\frac{11}{3}$
2. $A=\pi r^2 + \pi rl$
3. Not divisible
4. Mean = $-4$
5. Angles = $38^\circ$, $67^\circ$, $75^\circ$