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postnew [5]
2 years ago
9

Solve the system by substitution -x - y - z = -8 -4x + 4y + 5z = 7 2x + 2z = 4

Mathematics
2 answers:
zhuklara [117]2 years ago
7 0

Answer:  The required solution of the given system is

x = 3, y = 6 and z = -1.

Step-by-step explanation:  We are given to solve the following system of equations by the method of substitution :

-x-y-z=-8~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)\\\\-4x+4y+5z=7~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(ii)\\\\2x+2z=4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(iii)

From equation (iii), we have

2x+2z=4\\\\\Rightarrow x+z=2\\\\\Rightarrow x=2-z~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(iv)

Substituting the value of x from equation (iv) in equations (i) and (ii), we get

-(2-z)-y-z=-8\\\\\Rightarrow 2-z+y+z=8\\\\\Rightarrow 2+y=8\\\\\Rightarrow y=8-2\\\\\Rightarrow y=6

and

-4(2-z)+4y+5z=7\\\\\Rightarrow -8+4z+4\times6+5z=7\\\\\Rightarrow 9z+16=7\\\\\Rightarrow 9z=-9\\\\\Rightarrow z=-\dfrac{9}{9}\\\\\Rightarrow z=-1.

From equation (iii), we get

2x+2(-1)=4\\\\\Rightarrow 2x=6\\\\\Rightarrow x=\dfrac{6}{2}\\\\\Rightarrow x=3.

Thus, the required solution of the given system is

x = 3, y = 6 and z = -1.

gulaghasi [49]2 years ago
5 0

Answer: 14

Step-by-step explanation:

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The grades on a history midterm at Gardner Bullis are roughly symmetric with μ = 69 μ=69mu, equals, 69 and σ = 3.5 σ=3.5sigma, e
katrin2010 [14]

Answer:

-1.14

Step-by-step explanation:

The given information in statement is

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X=65

The Z score can be computed as

z=\frac{x-mean}{standard deviation}

z=\frac{65-69}{3.5}

z=-1.1429

z=-1.14 (rounded to two decimal places).

Thus, the computed z-score for Ishaan's exam grade is -1.14.

4 0
2 years ago
Triangle ABE is similar to triangle ACD. AED and ABC are straight lines. EB and DC are parallel. AE = 5 cm, BC = 4.5 cm, BE = 4
lianna [129]

Answer:

y = 16x/65

Step-by-step explanation:

Given:

Triangle ABE is similar to triangle ACD. AED and ABC are straight lines

EB and DC are parallel

The area of quadrilateral BCDE = xcm²

The area of triangle ABE = ycm²

Find attached the diagram from the above information.

In similar triangles, the ratio of their corresponding angles are equal.

Also, the ratio of the area of the two triangles = square of ratio of the corresponding sides of the two triangles.

Area ∆ACD/area of ∆ABE = (DC/EB)²

Area ∆ACD/area of ∆ABE = [(area of quadrilateral BCDE +

area of ∆ABE)]/(area of ∆ABE)

(x+y)/y = (DC/EB)²

(x+y)/y = (9/4)²

x+y = (81/16)y

x = (81/16)y - y

x = (81y - 16y)/16

x = 65y/16

Making y subject of formula

16x = 65y

y = 16x/65

An expression for y in terms of x:

y = 16x/65

3 0
1 year ago
Graph on a coordinate plane each set of (x, y) values. Which set of values describes two quantities that are in a proportional r
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Step-by-step explanation:

A proportional relationship occurs only with a linear relationship that goes through the origin.

8 0
2 years ago
Jeremy rides his bike at a rate of 15 miles per hour. Below is a table that represents the number of hours and miles Kevin rides
TiliK225 [7]

The correct answer would be, Jeremy rides at a greater speed than Kevin.

Step-by-step explanation:

Jeremy rides at a rate of 15 miles per hour

Kevin rides at a rate given in the table

Let Y be the distance traveled by Jeremy

And X be the number of hours

Then for Jeremy:

y/x = 15/1

=> y= 15 x

For Kevin:  

(46-23)/(4-2)

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So for Kevin, Y = 11.5 x

So when Jeremy's and Kevin's rates are compared,

15 > 11.5

which means Jeremy rides at a greater speed.  

Learn more about Time and Distance problem at:

brainly.com/question/3581191

#LearnWithBrainly

3 0
2 years ago
Bob has a standard deck of playing cards. If he randomly draws a J, K, 2, and 2, what is the probability that the next card he d
Zielflug [23.3K]
1:104 because there are 52 cards in a deck and he already drew a king, so double the chances and get 1:104?
6 0
2 years ago
Read 2 more answers
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