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3 years ago

How do i substitute y=x to 3x+2y=20

Mathematics

2 answers:

never [62]3 years ago

6 0

Where ever u see a y change it to an x
3x+2(x)=20
5x=20
x=4

GrogVix [38]3 years ago

5 0

Hello there,

<span>How do i substitute y=x to 3x+2y=20

Answer : since both are equal , you can change the letters to the same one.
3x + 2x = 20
5x = 20
x = 5
Therefore y = 5

Hope This Helps You!
Good Luck Studying :)</span>

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Considering the number of questions incorrect from classmates on a quiz {10, 11, 12, 13, 13, 13, 14, 15, 16, 16, 17, 18, 18, 19,

IrinaK [193]

Answer:

According to the Empirical Rule, 68% of the data should fall between 11.98 and 18.02

Step-by-step explanation:

We are given the following data in the question:

10, 11, 12, 13, 13, 13, 14, 15, 16, 16, 17, 18, 18, 19, 20

Formula:

$\text{Standard Deviation} = \sqrt{\displaystyle\frac{\sum (x_i -\bar{x})^2}{n-1}}$

where $x_i$ are data points, $\bar{x}$ is the mean and n is the number of observations.

$Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}$

$Mean =\displaystyle\frac{225}{15} = 15$

Sum of squares of differences = 25 + 16 + 9 + 4 + 4+ 4 + 1 + 0+ 1+ 1 + 4 + 9 + 9+ 16 + 25 = 128

$S.D = \sqrt{\dfrac{128}{14}} = 3.02$

Empirical rule:

According to this rule almost all the data lies within three standard deviation of the mean for a normal distribution.
About 68% of data lies within one standard deviation of the mean.
About 95% of data lies within two standard deviations of mean.
Arround 99.7% of data lies within three standard deviation of mean.

Thus, by empirical rule,

$\mu \pm 1\sigma = 15\pm (3.02) = (11.98,18.02)$

According to the Empirical Rule, 68% of the data should fall between 11.98 and 18.02

5 0

3 years ago

Write the equation of a rational function g(x) with vertical asymptotes at x = -3 and x = 3 , a horizontal asymptote at y = -4 a

Bezzdna [24]

Answer:

The equation for rational function for given asymptotes is

f(x)=(-4x^2-6)/{(x-3)(x+3)}

Step-by-step explanation:

Given:

vertical Asymptotes at x=3 and x=-3 and a horizontal asymptote at

y=-4 i.e parallel to x axis.

To find:

equation of a rational function i.e function in form p/q

Solution;

the equation should be in form of p/q

Numerator :denominator.

Consider f(x)=g(x)/h(x)

as vertical asymptote are x=-3 and x=3

denominator becomes, (x-3) and (x+3)

for horizontal asymptote to exist there should have same degrees in numerator and denominator which of '2'

when g(x) will be degree '2' with -4 as coefficient and dont have any real.

zero.

By horizontal asymptote will be (-4x^2 -6)

The rational function is given by

f(x)=g(x)/h(x)

={(-4x^2-6)/(x-3)(x+3)}.

3 0

3 years ago

A collection of 19 coins consisting of nickels and dimes is worth $1.35. How many dimes are there

pshichka [43]

Answer:

There are 8 dimes there.

Step-by-step explanation:

This question is solved used a system of equations.

I am going to say that:

x is the number of nickels.

y is the number of dimes.

19 coins

This means that x + y = 19.

A nickel is worth $0.05. A dime is worth $0.1. The total of these coins is $1.35. So

0.05x + 0.1y = 1.35

How many dimes are there?

We have to find y.

From the first equation: x = 19 - y.

Replacing in the second:

0.05(19 - y) + 0.1y = 1.35

0.95 - 0.05y + 0.1y = 1.35

0.05y = 0.4

y = 0.4/0.05

y = 8

There are 8 dimes there.

3 0

3 years ago

Find the perimeter and the area of each shape. Give your answer as a completely simplified exact value in terms of π (no approxi

nydimaria [60]

Answer:

Circumference: 12π + 8 cm,

Area: 48 ( cm )^2

Step-by-step explanation:

This figure is composed of circles, squares, and semicircles. As you can see, the squares indicate that each semicircle should have ( 1 ) the same area, and ( 2 ) the same length ( circumference ). It would be easier to take the circumference of the figure first, as it is composed of arcs part of semicircles the same length.

Circumference of 1 semicircle = $\frac{1}{2}$ ( πd ) = $\frac{1}{2}$ π( 4 ) = 2π ( cm )

Circumference of Figure (composed of 6 semicircles + 2 sides of a square),

We know that 6 semicircles should be 6 $*$ 2π, and as the sides of a square are equal - if one side is 4 cm, the other 3 are 4 cm as well. Therefore the " 2 sides of a square " should be 2

Circumference of Figure = 6 $*$ 2π + 2 = 12π + 8 ( cm )

_____________

The area of this figure is our next target. As you can see, it is composed of 3 semicircles, and the area of 3 semicircles subtracted from the area of 3 squares. Therefore, let us calculate the area of 1 semicircle, and the area of 1 square first.

Area of 1 semicircle = 1/2π $r^2$ = 1/2π $(2)^2$ = 2π ( cm ),