1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
iren [92.7K]
4 years ago
11

Solve the system using substitution.

Mathematics
1 answer:
Maru [420]4 years ago
5 0

Answer:

Given: The following system:

4x + y − 2z=18          ......[1]

2x-3y+3z = 21          ......[2]

x-3y=6                      ......[3]

we can write equation [3] as;

3y = x-6                     ......[4]

Multiply by 3 in equation [1] to both sides of an equation we get,

3 \cdot(4x+y-2z)= 3\cdot 18 or

12x+3y-6z=54              ......[5]

Substituting the equation [4] in [2] and [5] we get;

2x-(x-6)+3z=21 or

2x-x+6+3z=21

Simplify:

x+3z=15            .....[6]                       [combine like terms]

12x+x-6-6z =54

Simplify:

13x-6z=60         ......[7]        [Combine like terms]

On Solving equation [6] and [7] simultaneously,

x+3z=15

13x-6z=60

we get the value of x

i.e, x=6

Substitute the value of x in equation x+3z=15  we get

6+3z=15 or

3z=9

Simplify:

z=3

Also, substitute the value of x=6 in equation [3] we get the value of y;

x-3y=6

6-3y=6 or

-3y = 0

Simplify:

y = 0

Therefore, the solution to the system of three linear equation is, (6, 0 , 3)


You might be interested in
Graph -3x + 9y = -27
serious [3.7K]

Answer:

So the x-intercept is (9,0) and the y-intercept is (0,-3).

So I'm going to graph both points and connect them with a straight-edge.

Step-by-step explanation:

I would graph this using it's x- and y-intercepts.

To find the x-intercept, set y=0.

-3x+9(0)=-27

-3x+0=-27

-3x=-27

Divide both sides by -3:

x=9

To find the y-intercept, set x=0:

-3(0)+9y=-27

 0  +9y=-27

       9y=-27

Divide both sides by 9:  

        y=-3

So the x-intercept is (9,0) and the y-intercept is (0,-3).

So I'm going to graph both points and connect them with a straight-edge.

3 0
3 years ago
In a certain school there are 180 pupils in the year7,110 pupils study french,88 study German , and 65 indonesian.40 pupils stud
MAXImum [283]

Answer:

(a) All three languages  - 9

(b) Indonesian only  - 10

(c) none of the languages - 12

(d) At least one language  - 168

(e) Either one or two of the three languages - 159​

Step-by-step explanation:

The question require the knowledge of Set theory and its Formulas.

Total pupils = 180

French (Let F) = 110  

German (Let G) = 88

Indonesian (Let I) =  65

French and German (F intersection G) =  40

German and Indonesian (G intersection I) =  38

French and Indonesian (F intersection I)  = 26

German only  = 19

(a) All three languages

We are given only German speaking people are 19

Only German = n(G) - n( F intersection G) - n(G intersection I) + n(F intersection G intersection I)

 19 = 88 - 40-38 + n(G intersection I) + n(F intersection G intersection I)

n(G intersection I) + n(F intersection G intersection I) = 9

n(G intersection I) + n(F intersection G intersection I) represents the number of pupils speaking who study all the three languages.

(b)Indonesian only

   n( I) - n(G intersection I) + n(F intersection I) + n(G intersection I) + n(F intersection G intersection I)

65 - 38 - 26 + 9 = 10

So 10 pupils speak Indonesian only

(c)none of the languages

It will be equal to Total - pupils speaking any of the three languages

Any of the three languages = (F union G union I)

  = n(F) +n(G) + n(I) -n(F intersection G) - n(G intersection I) -n(F intersection I)

    +  n(F intersection G intersection I)

n(G intersection I)

  = 110 + 88 + 65 -40 -38-26 + 9

  = 263 - 95

   = 168

So 168 pupils speak any of the three languages

None speakers = 180 - 168 = 12 pupils

So 12 pupils do not speak any of the three languages.

(d)at least one language

At least one language has the meaning that the person can either speak one two or all three languages, so it will be same as we proceeded above

Any of the three languages = (F union G union I)

  = n(F) +n(G) + n(I) -n(F intersection G) - n(G intersection I) -n(F intersection I)

    +  n(F intersection G intersection I)

n(G intersection I)

  = 110 + 88 + 65 -40 -38-26 + 9

  = 263 - 95

   = 168

(e) either one or two of the three languages​

Pupils can speak one or two language but not all the three so will subtract all the three language speaker from the total.

  Total speaker = 168

 All three languages speaker  = 9

 Either one or two of the three languages​ speaker = 168 - 9 = 159

8 0
4 years ago
Simplify 33/34 divided by 66/85
GREYUIT [131]
The answer would be 1  1/4, or 1.25.
5 0
4 years ago
Read 2 more answers
What is the value of the expression?<br><br> 5(912−14)+0.5
Dmitrij [34]
<span>5(912−14)+0.5
= </span><span>5(898) +0.5
= 4490 + 0.5
= 4490.5</span>
6 0
3 years ago
Read 2 more answers
Can y’all help me with ! I need correct anwsers ! Please
serious [3.7K]

Answer:

-0.875

Step-by-step explanation:

So you have the points -4.25 and 2.50. To find the midpoint you simply add the two and then divide by 2. This results in (-4.25 + 2.50) / 2 = -0.875

4 0
2 years ago
Read 2 more answers
Other questions:
  • A + 4 = 6, when a = 2. true false open
    11·2 answers
  • If you need to fill a cylinder with liquid to clean your house and the cylinder measure
    5·1 answer
  • What is the value of X?
    8·1 answer
  • The perimeter of a rectangle is 42 inches. the length is twice the width. What are the dimensions? What is the area?
    14·1 answer
  • Which is closest to 1?<br> A) 1.2<br> B) 0.1<br> C) 0.01<br> D) 0.9
    11·2 answers
  • What is 115÷5 using distributive properties
    13·1 answer
  • Segments AD and BE are parallel because they are both horizontal
    12·1 answer
  • What is the sum of r? - 3x + 7 and 3x2 + 5x - 9?
    5·1 answer
  • A garden table and a bench cost $783 combined. The garden table costs $83 more than the bench. What is the cost of the bench?
    8·1 answer
  • Thaddeus shakes his head as he pays $12.37 to the clerk for lunch. Complaining to a friend, Thaddeus says, “Do you realize that
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!