Yes you are right it's C)
Notice that f(-2) = (-2)³ +2( - 2)² + 4(-2) + 8 =0
Then x³+2x²+4x+8 is divisible by (x+2)
Perform this division & you will get:

x³+2x²+4x+8 = (x+2)(x²+4)
The root of (x+2) is the value that render it nil, that is x=-2
The root of (x²+4) are imaginary (not real) because
x²+4 =0 ==> x² = -4 & x=√-4 or x= 2i (nor real).
Hope you understood the reasoning

3 0

3 years ago

The angles in a triangle are in the ratio 1:2:3. Show that the triangle is a right - angled triangle.

Alja [10]

Answer:

Angles in a triangles add up to 180°

Respectively 1 : 2 : 3 is going to be 1 x , 2 x and 3 x so,

1 x + 2 x + 3 x = 180°

⇒ Simplify

6 x = 180°

⇒ Divide by 6 on both sides to isolate x

x = 30°

Since the ratio was 1 x : 2 x : 3 x and x is 30°,

30 : 60 : 90

And since there is a 90° angle, it is a right - angled triangle

4 0

3 years ago

In ΔUVW, w = 44 cm, u = 83 cm and ∠V=141°. Find the area of ΔUVW, to the nearest square centimeter.

Tema [17]

Answer:

$Area \approx 1149\ cm^2$

Step-by-step explanation:

<u>Given that:</u>

ΔUVW,

Side w = 44 cm, (It is the side opposite to $\angle W$ )

Side u = 83 cm (It is the side opposite to $\angle U$ )

and ∠V=141°

Please refer to the attached image with labeling of the triangle with the dimensions given.

Area of a triangle with two sides given and angle between the two sides can be formulated as:

$A = \dfrac{1}{2}\times a\times b\times sinC$

Where a and b are the two sides and

$\angle C$ is the angle between the sides a and b

Here we have a = w = 44cm

b = u = 44cm

and ∠C= ∠V=141

Putting the values to find the area:

$A = \dfrac{1}{2}\times 44\times 83\times sin141\\\Rightarrow A = \dfrac{1}{2} \times 3652 \times sin141\\\Rightarrow A =1826 \times 0.629\\\Rightarrow A \approx 1149\ cm^2$