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3 years ago

8

khan academy is giving me only this explanation but won't go into detail and I cannot understand it for the life of me. how do I

know what number to multiply both variables by? what exactly does expanding the parentheses mean? help

1 answer:

Setler [38]3 years ago

7 0

Answer:

12 - 4i

Step-by-step explanation:

-2i ( 2+6i)

Distribute

-2i * 2 + -2i *6i

-4i - 12 i^2

We know that i^2 = -1 so replace it

-4i - 12(-1)

-4i + 12

Then put in the order a+bi where the real number comes first and the imaginary number comes last

12 - 4i

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What is the sum or difference?

dlinn [17]

1. Ans: Option (B) $-6x^4$

Explanation:
Given: $2x^4 - 8x^4$
Take the common out:
=> $x^4(2 - 8)$

Hence: => $[tex]-6x^4$ [/tex] (Option B)

2. Ans: Option (D) $-3y^5$

Explanation:
Given: $6y^5 - 9y^5$
Take the common term(s) out:
=> $y^5(6-9)$

Hence: => $-3y^5$ (Option D)

3. Ans: Option (B) $9x^2 - 12x + 6$ <span> quadratic trinomial

Explanation:
</span>Given: $6 - 12x + 13x^2 - 4x^2$

The standard form of polynomial function must have the highest powered value at the start, then the second highest and so on.

=> $13x^2 - 4x^2 - 12x + 6$
=> $9x^2 - 12x + 6$ (Option B)

4. Ans: Option (C) $7.3x^2 + 0.8x + 1.3$

Explanation:
In order to find the total number of C<span>ommon and Endler's guppies, you need to add both Common and Endler's guppies' polynomials, as follows:

</span>Common guppies: $3.1x^2 +6.0x + 0.3$ <span>
Endler's guppies: </span> $4.2x^2 - 5.2x + 1.0$
(add both)
-----------------------------------------------------------------
Total number: $7.3x^2 +0.8x + 1.3$
-----------------------------------------------------------------
Hence the ans is Option(C) $7.3x^2 + 0.8x + 1.3$

5. Ans: Option (D) $2x^2(133 - 18 \pi )$

Explanation:
First let's find the total area of the yard:
Total Area of the Yard = 14x * 19x = $266x^2$

Now the area of the circular fountain:
Area of the Circular Fountain = $\pi r^2$
Since, r=6x
Therefore,
Area of the Circular Fountain = $\pi (6x)^2 = 36 \pi x^2$

Now the final Area of the yard would be:
Final area of the Yard = Total Area of the Yard - Area of the Circular Fountain
Final area of the Yard = $266x^2$ - $36 \pi x^2$
=> Final area of the Yard = $2x^2(133 - 18 \pi)$ (Option D)

6. Ans: Option (A) $56x^2$

Explanation:
First let's find the total area of the lot:
Total Area of the lot= 6x * 10x = $60x^2$

Now the area of the stadium:
Area of the stadium = 1x * 4x = $4x^2$

Now the final Area of the lot would be:
Final area of the lot= Total Area of the lot - Area of the stadium
Final area of the lot= $60x^2$ - $4x^2$
=> Final area of the lot = $56x^2$ (Option A)

-i

4 0

3 years ago

Read 2 more answers

A robot can complete 3 tasks in 2/5 hour. Each task takes the same amount of time. a. How long does it take the robot to complet

Elena L [17]

It takes 8 minutes
The robot can complete 7.5 tasks in an hour

3 0

3 years ago

Read 2 more answers

Solve the inequality –8 < x – 14.

Ilya [14]

Answer:

x=6

Step-by-step explanation:

7 0

3 years ago

Read 2 more answers

1. Find the measure of the side indicated (x). Round to the nearest tenth. Show your work to support your

lidiya [134]

Answer:

Is this for a Trig class? just wondering

Step-by-step explanation:

Use SOH CAH TOA to recall how the trig functions fit on a triangle

SOH: Sin(Ф)= Opp / Hyp

CAH: Cos(Ф)= Adj / Hyp

TOA: Tan(Ф) = Opp / Adj

we want to find the Hypotenuse (Hyp) and are given an angle and the adjacent side (adj) sooo use CAH , b/c it has all of the pieces

Cos(37) = Adj / Hyp

Cos(37) = 11 / Hyp

swap Cos(37) and Hyp... an algebra trick you should know from college algebra or where ever you learned algebra

Hyp = 11 / Cos(37)

now solve with your handy TI 83 / 84 / 89 calculator :) if you don't have one go get one . :D get the 89 if you are going into engineering classes... the 83 /84 if not. (obviously there are many many other good choices, i'm not really a calculator salesman on the side :D )

Hyp = 13.77349...

Hyp = 13.8 ( rounded to nearest 10th ) :)

3 0

3 years ago

A carpenter makes and sells rocking chairs. The material for each chair costs $22.50. The chairs sell for $75 each. If the charp

Lady_Fox [76]

Answer:

About 6 chairs

Step-by-step explanation:

75x=22.50+420

75x=442.5

x=5.9

So about 6 chairs

4 0

3 years ago