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3 years ago

The problem below has been solved incorrectly. Identify and explain the error.

Mathematics

1 answer:

mylen [45]3 years ago

7 0

Answer:

If you look over the steps you can see that until 4x + x + 3 = 18, evertything is dandy. But the step after that 4x + x =21 seems a bit fishy.

Think about it they subtract 3 from both sides so the first side is correct

4x + x, but they added 3 to the other side:

$(4x+x+3) - 3 = 18 - 3\\4x+x = 15$

not

4x+x = 21

Then we solve for 4x + x = 15

$5x = 15\\x = \frac{15}{5} \\x = 3$

To solve for y we use :

y = x+3

y = 3+3 = 6

so (3,6) is the right answer

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Please show full solutions! WIll Mark Brainliest for the best answer. <br><br> SERIOUS ANSWERS ONLY

Ierofanga [76]

Answer:

vertical scaling by a factor of 1/3 (compression)
reflection over the y-axis
horizontal scaling by a factor of 3 (expansion)
translation left 1 unit
translation up 3 units

Step-by-step explanation:

These are the transformations of interest:

g(x) = k·f(x) . . . . . vertical scaling (expansion) by a factor of k

g(x) = f(x) +k . . . . vertical translation by k units (upward)

g(x) = f(x/k) . . . . . horizontal expansion by a factor of k. When k < 0, the function is also reflected over the y-axis

g(x) = f(x-k) . . . . . horizontal translation to the right by k units

Here, we have ...

g(x) = 1/3f(-1/3(x+1)) +3

The vertical and horizontal transformations can be applied in either order, since neither affects the other. If we work left-to-right through the expression for g(x), we can see these transformations have been applied:

vertical scaling by a factor of 1/3 (compression) . . . 1/3f(x)
reflection over the y-axis . . . 1/3f(-x)
horizontal scaling by a factor of 3 (expansion) . . . 1/3f(-1/3x)
translation left 1 unit . . . 1/3f(-1/3(x+1))
translation up 3 units . . . 1/3f(-1/3(x+1)) +3

_____

<em>Additional comment</em>

The "working" is a matter of matching the form of g(x) to the forms of the different transformations. It is a pattern-matching problem.

The horizontal transformations could also be described as ...

translation right 1/3 unit . . . f(x -1/3)
reflection over y and expansion by a factor of 3 . . . f(-1/3x -1/3)

The initial translation in this scenario would be reflected to a translation left 1/3 unit, then the horizontal expansion would turn that into a translation left 1 unit, as described above. Order matters.

8 0

2 years ago

All of the following expressions have the same value except _____.

Mariana [72]

All of them have the same answer of -8 except the last one.

4 0

3 years ago

Read 2 more answers

Given z1 and z2 below. Calculate z1/z2 and write your answer in rcistheta form.

andre [41]

Answer:

(2/9)cis(30°)

Step-by-step explanation:

We can express the two numbers in magnitude∠angle form, then find their ratio.

|z1| = 3√((-1)² +(√3)²) = 3√4 = 6

∠z1 = arctan((3√3)/(-3)) = -arctan(√3) = 120°

z2 = 27∠90°

So, the ratio is ...

z1/z2 = (6∠120°)/(27∠90°) = (6/27)∠(120°-90°)

z1/z2 = (2/9)∠30°

8 0

3 years ago

The government of the Republic of Lemon Island plans to transform their lemon-based economy into a tourism-based economy. They d

NNADVOKAT [17]

Step-by-step explanation:

dy/dt = (A − Be^(-t/5)) y

(a) First, find the general solution by separating the variables and integrating.

dy / y = (A − Be^(-t/5)) dt

dy / y = [A + 5B (-⅕ e^(-t/5))] dt

ln |y| = At + 5B e^(-t/5) + C

y = e^(At + 5B e^(-t/5) + C)

y = Ce^(At + 5B e^(-t/5))

Given that A = 0.06, B = 0.04, and y(0) = 50×10⁶ − 10×10⁶ = 40×10⁶:

40×10⁶ = Ce^(0.06(0) + 5(0.04) e^(-0/5))

40×10⁶ = Ce^(0.2)

C = 40×10⁶ e^(-0.2)

y = 40×10⁶ e^(-0.2) e^(0.06t + 0.2 e^(-t/5))

y = 40×10⁶ e^(-0.2 + 0.06t + 0.2 e^(-t/5))

(b) If A = 0.02 and B = 0, and there is no transformation (y(0) = 50×10⁶), then:

50×10⁶ = Ce^(0.02(0) + 0)

50×10⁶ = C

y = 50×10⁶ e^(0.02t)

Comparing to the answer from part (a):

40×10⁶ e^(-0.2 + 0.06t + 0.2 e^(-t/5)) = 50×10⁶ e^(0.02t)

e^(-0.2 + 0.04t + 0.2 e^(-t/5)) = 5/4

-0.2 + 0.04t + 0.2 e^(-t/5) = ln(5/4)

-5 + t + 5e^(-t/5) = 25 ln(5/4)

t + 5e^(-t/5) = 5 + 25 ln(5/4)

Solve with a calculator:

t = 9.886

The transformed economy surpasses the untransformed economy in the 10th year.

y = 40×10⁶ e^(-0.2 + 0.06(5) + 0.2 e^(-5/5))

y = 47.6×10⁶

The percent growth is:

(47.6×10⁶ − 40×10⁶) / 40×10⁶ × 100% = 19%

The growth rate is greater than 4%, so the current government can expect to be reelected.

3 0

3 years ago

An economist is studying the linear relationship between the selling price p, of a

dimulka [17.4K]

Answer:

The equation that represents the number of persons buying the phone and the price of the phone is y = -0.75·x + 60

Step-by-step explanation:

The given data are as follows

x, p($)

10, 52.5

25, 41.25

40, 30

60, 15

We note that a plot of the given points give a straight line graph indicating a linear relationship

The rate of change of p($) with x is given by slope, m in the following relation;

$Slope, \, m =\dfrac{y_{2}-y_{1}}{x_{2}-x_{1}}$

Which gives;

$Slope, \, m =\dfrac{41.25-52.5}{25-10} = \dfrac{30-41.25}{40-25} = \dfrac{15-30}{40-60} =-0.75$

Therefore, to write the equation in slope and intercept form, we have;

From the first point with coordinates (52.5, 10), we have

y - 52.5 = -0.75×(x - 10)

y = -0.75·x + 7.5 + 52.5 = -0.75·x + 60

The equation that represents the number of persons buying the phone and the price of the phone is y = -0.75·x + 60.

4 0

3 years ago