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3 years ago

What are the possible values of x if (4x - 5)2 = 49? Check all that apply. uw we we

Mathematics

1 answer:

kogti [31]3 years ago

7 0

Answer:

x = - $\frac{1}{2}$ , x = 3

Step-by-step explanation:

Given

(4x - 5)² = 49 ( take the square root of both sides )

4x - 5 = ± $\sqrt{49}$ = ± 7 ( add 5 to both sides )

4x = 5 ± 7, thus

4x = 5 - 7 = - 2 ( divide both sides by 4 )

x = $\frac{-2}{4}$ = - $\frac{1}{2}$

4x = 5 + 7 = 12 ( divide both sides by 4 )

x = 3

As a check

Substitute these values into the left side of the equation and if equal to the right side then they are the solutions.

x = - $\frac{1}{2}$

left side = (- 2 - 5)² = (- 7)² = 49 = right side ⇒ solution

x = 3

left side = (12 - 5)² = 7² = 49 = right side ⇒ solution

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PLEASE HELP QWQ AsAp with these 4 questions

den301095 [7]

Answer:

Step-by-step explanation:

I can't believe I'm doing this for 5 points, but ok!

For the first 3, we are going to multiply to find the value of that 3 x 3 matrix by picking up the first 2 columns and plopping them down at the end and then multiplying through using the rules for multiplying matrices:

$\left[\begin{array}{ccccc}7&4&6&7&4\\-4&8&9&-4&8\\1&8&7&1&8\end{array}\right]$ and from there find the sum of the products of the main axes minus the sum of the products of the minor axes, as follows (I'm not going to state the process in the next 2 problems, so make sure you follow it here. This is called the determinate. The determinate is what you get when you evaluate or find the value of a matrix. Just so you know):

$(7*8*7)+(4*9*1)+(6*-4*8)-[(1*8*6)+(8*9*7)+(7*-4*4)]$ which gives us:

392 + 36 - 192 - [48 + 504 - 112] which simplifies to

236 - 440 which is -204

On to the second one:

$\left[\begin{array}{ccccc}-8&-4&-1&-8&-4\\1&7&-3&1&7\\8&9&9&8&9\end{array}\right]$ and multiplying gives us

$(-8*7*9)+(-4*-3*8)+(-1*1*9)-[(8*7*-1)+(9*-3*-8)+(9*1*-4)]$ which gives us:

-504 + 96 - 9 - [-56 + 216 - 36] which simplifies to

-417 - 124 which is -541, choice c.

Now for the third one:

$\left[\begin{array}{ccccc}-2&-2&-5&-2&-2\\2&7&-3&2&7\\8&9&9&8&9\end{array}\right]$ and multiplying gives us

$(-2*7*9)+(-2*-3*8)+(-5*2*9)-[(8*7*-5)+(9*-3*-2)+(9*2*-2)]$ which gives us:

$-126+48-90-[-280+54-36]$ which simplifies to

-168 - (-262) which is 94, choice c again.

Now for the last one. I'll show you the set up for the matrix equation; I solved it using the inverse matrix. So I'll also show you the inverse and how I found it.

$\left[\begin{array}{cc}-4&-5&\\-6&-8\\\end{array}\right]$ $\left[\begin{array}{c}x\\y\\\end{array}\right]$ = $\left[\begin{array}{c}-5\\-2\\\end{array}\right]$ and I found the inverse of the 2 x 2 matrix on the left.

Find the inverse by:

* finding the determinate

* putting the determinate under a 1

* multiply that by the "mixed up matrix (you'll see...)

First things first, the determinate:

|A| = (-4*-8) - (-6*-5) which simplifies to

|A| = 32 - 30 so

|A| = 2; now put that under a 1 and multiply it by the mixed up matrix. The mixed up matrix is shown in the next step:

$\frac{1}{2}\left[\begin{array}{cc}-8&5\\6&-4\end{array}\right]$ (to get the mixed up matrix, swap the positions of the numbers on the main axis and then change the signs of the numbers on the minor axis). Now we multiply in the 1/2 to get the inverse:

$\left[\begin{array}{cc}-4&\frac{5}{2}\\3&-2\\\end{array}\right]$ Multiply that inverse by both sides of the equation. This inverse "undoes" the matrix that's already there (like dividing the matrix that's already there by itself) which leaves us with just the matrix of x and y. Multiply the inverse matrix by the solution matrix:

$\left[\begin{array}{c}x&y\end{array}\right] =\left[\begin{array}{cc}-4&\frac{5}{2} \\3&-2\end{array}\right] *\left[\begin{array}{c}-5&-2\\\end{array}\right]$ and that right side multiplies out to

x = 20 - 5 which is

x = 15 and

y = -15 + 4 which is

y = -11

(It works, I checked it)

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3 years ago

A box with a square base and open top must have a volume of 237276 cm^3. We wish to find the dimensions of the box that minimize

svp [43]

Answer:

$A(x)=\dfrac{x^3+949104}{x}$

Step-by-step explanation:

Given a box with a square base and an open top which must have a volume of 237276 cubic centimetre. We want to find a formula for the surface area of the box in terms of only x, the length of one side of the square base.

Let the side length of the base =x

Let the height of the box =h

Since the box has a square base

Volume,

$V=x^2h=237276\\\\h=\dfrac{237276}{x^2}$

Surface Area of the box = Base Area + Area of 4 sides

$Area, A(x,h)=x^2+4xh$

Substitute h derived above into A(x,h)

$Area=x^2+4x(\frac{237276}{x^2})\\\\A(x)=x^2+\dfrac{949104}{x}\\\\A(x)=\dfrac{x^3+949104}{x}$

Therefore, a formula for the surface area of the box in terms of only x, the length of one side of the square base is:

$A(x)=\dfrac{x^3+949104}{x}$

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4 years ago

If f(x)=|x|, sketch f'(x) for -2

Luden [163]

Answer:

Step-by-step explanation:

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3 years ago

What 15 by 15 I need to know!!

Colt1911 [192]

15 times 15 = 225. :) since i helped you, can you help me? My question: <span>brainly.com/question/2967131</span>

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4 years ago

Read 2 more answers

M&M plain candies come in various colors. According to the M&M/Mars Department of Consumer Affairs, the distribution of

lyudmila [28]

Answer:

A) 0.12. Yes. Choosing a green and blue M&M is possible

B) 0.43. Yes. Choosing a yellow and red M&M is possible

C) 0.78

Step-by-step explanation:

First of all, the summation of the distribution of all colours is;

Σ(all colors ) = 22% + 20% + 23% + 10% + 6% + 6% + 13% = 100%, or 1.

Thus;

a) P(green candy or blue candy) is;

P(GREEN ∪ BLUE) = P(G) + P(BL)

P(GREEN ∪ BLUE) = 6%+6%

P(GREEN ∪ BLUE) = 12% or 0.12

Now, due to the fact that we have to choose ONE candy and only ONE candy at random, then they are mutually exclusive: Yes. Choosing a green and blue M&M is possible

b)P(yellow candy or red candy is;

P(YELLOW ∪ RED) = P(Y) + P(R)

P(YELLOW ∪ RED) = 20% + 23% = 43% or 0.43

Yes. Choosing a yellow and red M&M is possible

c) P(NOT PURPLE)

the probability of having a purple is;

P(PURPLE) = 22% or 0.22

So, the Probability of NOT having a PURPLE is 1 - 0.22 = 0.78

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3 years ago