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2 years ago

Y=2x-5 x+y=7 solve by elimination

Mathematics

2 answers:

marta [7]2 years ago

7 0

Answer:

x = 4

y = 3

Step-by-step explanation:

First, reorder the first equation to make it into the same format as the second equation:

y = 2x - 5

-2x + y = -5

Then, put the equations together:

-2x + y = -5

x + y = 7

Solve by elimination by multiplying the bottom equation by 2, then add the equations together and solve for y:

-2x + y = -5

2x + 2y = 14

3y = 9

y = 3

Then, plug in 3 as y into one of the equations to solve for x:

y = 2x - 5

3 = 2x - 5

8 = 2x

4 = x

So, the answer is x = 4 and y = 3

kenny6666 [7]2 years ago

6 0

Answer:

x=4

y=3

im 100% sure

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The average time an individual reads online national news reports is 49 minutes. Assume the standard deviation is 16 minutes and

Olin [163]

Answer:

0.118 is the probability someone will spend no more than 30 minutes reading online national news reports.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 49 minutes

Standard Deviation, σ = 16 minutes

We are given that the distribution of time an individual reads is a bell shaped distribution that is a normal distribution.

Formula:

$z_{score} = \displaystyle\frac{x-\mu}{\sigma}$

P(no more than 30 minutes)

$P( x \leq 610) = P( z \leq \displaystyle\frac{30 - 49}{16}) = P(z \leq -1.1875)$

Calculation the value from standard normal z table, we have,

$P(x \leq 30) = 0.118 = 11.8\%$

0.118 is the probability someone will spend no more than 30 minutes reading online national news reports.

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2 years ago

A gas pump measures volume of gas to the nearest 0.01 gallon. Which measurement shows an appropriate level of precision for the

Anon25 [30]

The answer would be (A) 14.47 gallons. Hope this helps!

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3 years ago

-1/24 + 2/7 = when you give me the answer you have to have a fration

Troyanec [42]

Answer:

41/168

Step-by-step explanation:

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2 years ago

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Find the missing side length of the triangie.<br> 12 in.<br> 35 in.

OlgaM077 [116]

Answer:

Step-by-step explanation:

Right Scalene Triangle

Side a = 37

Side b = 12

Side c = 35

Angle ∠A = 90° = 1.5708 rad = π/2

Angle ∠B = 18.925° = 18°55'29" = 0.3303 rad

Angle ∠C = 71.075° = 71°4'31" = 1.2405 rad

C=71.075°B=18.925°A=90°b=12a=37c=35

Area = 210

Perimeter p = 84

Semiperimeter s = 42

Height ha = 11.35135

Height hb = 35

Height hc = 12

Median ma = 18.5

Median mb = 35.51056

Median mc = 21.2191

Inradius r = 5

Circumradius R = 18.5

Vertex coordinates: A[0, 0] B[35, 0] C[0, 12]

Centroid: [11.66667, 4]

Inscribed Circle Center: [5, 5]

Circumscribed Circle Center: [17.5, 6]

6 0

2 years ago

Express the equation in rectangular form<br> a) r = 2sin(2Θ)<br> b) r = 4cos(3Θ)

Dafna11 [192]

Answer:

a. sqrt(x^2+y^2) * (x^2+y^2) = 4xy

b. (x^2+y^2)^2 = 4x{ (x^2 - 3 y^2}

Step-by-step explanation:

a) r = 2sin(2Θ)

r* = 2 sin 2 theta

We know sin 2theta = 2 sin theta cos theta

r = 2 * 2 sin theta cos theta

sin theta = y/r and cos theta = x/r

r = 4 y/r * x/r

r = 4xy / r^2

Multiply each side by r^2

r^3 = 4xy

r * r^2 = 4xy

We know r = sqrt(x^2+y^2) and r^2 = (x^2+y^2)

sqrt(x^2+y^2) * (x^2+y^2) = 4xy

b) r = 4cos(3Θ)

we know that cos 3 theta = cos^3(theta) - 3 sin^2(theta) cos(theta)

r = 4 *cos^3(theta) - 3 sin^2(theta) cos(theta)

Factor out a cos theta

r = 4 *cos(theta){ cos^2 (theta) - 3 sin^2(theta) }

We know that sin theta = y/r and cos theta = x/r

r = 4 (x/r) { (x/r)^2 - 3 (y/r)^2}

r = 4 *(x/r) { (x^2/r^2 - 3 y^2/r^2}

Multiply by r

r^2 = 4x { (x^2/r^2 - 3 y^2/r^2}

Multiply by r^2

r^2 *r^2 = 4x { (x^2 - 3 y^2}

r^4 = 4x{ (x^2 - 3 y^2}

We know r^2 = (x^2+y^2)

(x^2+y^2)^2 = 4x{ (x^2 - 3 y^2}

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2 years ago