Figure out the answer to each riddle below:

Can someone give me a step by step explanation because my teacher doesn’t teach us anything? :(

Alex

Answer:

(7x^2 -1)(x - 2).

Step-by-step explanation:

7x^3 - 14x^2 - x + 2

We can factor this by grouping - that is factoring the first 2 terms and the last 2:

= 7x^2(x - 2) - 1(x - 2) <-- the x - 2 is common to both parts so we have:

(7x^2 -1)(x - 2).

7 0

3 years ago

A) Change 2800 cm³ into litres. b) Change 12.4/ into cm³.

beks73 [17]

Answer:

2.8 liters

12400 cm^3

Step-by-step explanation:

a)

1000 cm^3 = 1 iter

2800 cm^3 * (1 liter)/(1000 cm^3) = 2.8 liters

b)

12.4 liters * (1000 cm^3)/(1 liter) = 12400 cm^3

5 0

3 years ago

Read 2 more answers

Y = -5 2x – 4y = 18 PLEASE HELP NO LINKS LINKS=REPORT

Ber [7]

Answer:

x= -1

Step-by-step explanation:

since y is -5 then we would put that in the second equation:

2x - 4(-5) = 18

then it’s:

2x + 20 = 18

Then we subtract 20 from both sides

2x = -2

Last we divide both by 2 and we get x = -1

5 0

3 years ago

Read 2 more answers

Drag and drop formal proof. Prove the Polygon Exterior Angle Sum Theorem for the enclosed triangle, that is ∠1+∠2+∠3=360°

jasenka [17]

Answer:

The sum of all the external angles of a triangle is 360°.

Step-by-step explanation:

Let there are n sides in a polygon.

So, there are n internal angles in the polygon, let ∠i1, ∠i2, ∠i3, ..., ∠in are the measure of n internal angles of the polygon.

The measure of external angle corresponding to ∠i1, ∠1= 180°-∠i1,

The measure of external angle corresponding to ∠i2, ∠2 = 180°-∠i2,

Similarly, the measure of external angle corresponding to ∠in, ∠n = 180°-∠in.

Now, the sum of all the external angles of the polygon,

(∠1+∠2+...+∠n)=(180°-∠i1)+(180°-∠i2)+...+(180°-∠in)

=(180°+180°+...n times)-(∠i1+∠i2+...+∠in)

=n x 180° - (∠i1+∠i2+...+∠in)

As ∠i1+∠i2+...+∠in is the sum of all the internal angles of the polygon.

So, the sum of all the external angles of the polygon =

(n x 180°) - (sum of all the internal angles of the polygon).

In the case of a triangle, n=3 and the sum of all the three internal angles, ∠i1+∠i2+∠i3 = 180°.

Therefore, the sum of all the external angles of a triangle,

∠1+∠2+∠3 =3x180°-(∠i1+∠i2+∠i3)

=540°=180°

=360°.

Hence, the sum of all the external angles of a triangle is 360°.

5 0

3 years ago

Of the students who eat in a certain cafeteria, each student either likes or dislikes lima beans and each student either likes o

spayn [35]

Answer: There are 32 students who like brussels sprouts but dislike beans.

Step-by-step explanation:

Since we have given that

Number of students eat in the cafeteria = 120

Fraction dislike lime beans = $\dfrac{2}{3}$

Fraction who dislike lime beans and brussles sprouts both = $\dfrac{2}{3}\times \dfrac{3}{5}$

Fraction who dislikes lime beans but not brussles is given by

$\dfrac{2}{3}(1-\dfrac{3}{5})\\\\=\dfrac{2}{3}\times \dfrac{2}{5}\\\\=\dfrac{4}{15}$

So, Number of students who like brussels sprouts but dislike lima beans is given by

$\dfrac{4}{15}\times 120\\\\=32$

Hence, there are 32 students who like brussels sprouts but dislike beans.

7 0

4 years ago