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
ArbitrLikvidat [17]
3 years ago
7

Solve the system by substitution(show your work)

Mathematics
1 answer:
Gnesinka [82]3 years ago
3 0

Answer:

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

Step-by-step explanation using substitution:

Solve the following system:

{-x - y - z = -8

-4 x + 4 y + 5 z = 7

2 x + 2 z = 4

In the first equation, look to solve for x:

{-x - y - z = -8

-4 x + 4 y + 5 z = 7

2 x + 2 z = 4

Add y + z to both sides:

{-x = -8 + y + z

-4 x + 4 y + 5 z = 7

2 x + 2 z = 4

Multiply both sides by -1:

{x = 8 - y - z

-4 x + 4 y + 5 z = 7

2 x + 2 z = 4

Substitute x = 8 - y - z into the second and third equations:

{x = 8 - y - z

4 y - 4 (8 - y - z) + 5 z = 7

2 (8 - y - z) + 2 z = 4

4 y - 4 (8 - y - z) + 5 z = 4 y + (-32 + 4 y + 4 z) + 5 z = -32 + 8 y + 9 z:

{x = 8 - y - z

-32 + 8 y + 9 z = 7

2 (8 - y - z) + 2 z = 4

2 (8 - y - z) + 2 z = (16 - 2 y - 2 z) + 2 z = 16 - 2 y:

{x = 8 - y - z

-32 + 8 y + 9 z = 7

16 - 2 y = 4

In the third equation, look to solve for y:

{x = 8 - y - z

-32 + 8 y + 9 z = 7

16 - 2 y = 4

Subtract 16 from both sides:

{x = 8 - y - z

-32 + 8 y + 9 z = 7

-2 y = -12

Divide both sides by -2:

{x = 8 - y - z

-32 + 8 y + 9 z = 7

y = 6

Substitute y = 6 into the second equation:

{x = 8 - y - z

9 z + 16 = 7

y = 6

In the second equation, look to solve for z:

{x = 8 - y - z

9 z + 16 = 7

y = 6

Subtract 16 from both sides:

{x = 8 - y - z

9 z = -9

y = 6

Divide both sides by 9:

{x = 8 - y - z

z = -1

y = 6

Substitute z = -1 into the first equation:

{x = 9 - y

z = -1

y = 6

Substitute y = 6 into the first equation:

{x = 3

z = -1

y = 6

Collect results in alphabetical order:

Answer:  {x = 3 , y = 6 , z = -1

You might be interested in
I've been having problems with this for a while...
Rina8888 [55]
Like all problems that involve images within the question, we should definitely try to draw this out. In the picture above, I have done this.

Now, we can see that this is just a simple proportion problem. For every 2.5 cm of height of the flower, we are 2 cm from the opening, or aperture. For every 20 cm of height, how far are we? We can set up the problem like this:

20 ............2.5
-------- = ---------
...x ............. 2

where x is the unknown distance to the aperture from the flower. Now, we just need to get x by itself. A typical way of solving something like this is by doing "butterfly multiplication" which is really just a shortcut haha. Anyway, I can rewrite that equation ^ as:

20×2 = 2.5 × x

Then, to solve for x, we would divide both sides by 2.5. (If you don't know why that is, please let me know and I'll elaborate).

We would then have:

20×2
------- = x
2.5

Which then simplifies to:

x = 16

Try using the same logic for your second question, and if you get stuck, I'd be happy to help! please let me know if any of this doesn't make sense. :)

3 0
3 years ago
At a baseball game, a vender sold a combined total of 240 sodas and hot dogs. The number of sodas sold was two times the number
olga55 [171]

Answer:

Sodas: 160

Hot Dogs: 80

Step-by-step explanation:

Sodas: s

Hot Dogs: d

s+d=240

s=2d

3d=240

d=80

s=160

7 0
3 years ago
Multiply=8 but add up to 7
m_a_m_a [10]
The to that problem is 56
4 0
3 years ago
Help plz gonna fail
sweet [91]

Step-by-step explanation:

for questions 5,6,7,8 you need to use formula

for questions 9.and 10 sorry I dunno how to do

6 0
2 years ago
Which first step for solving the given system using substitution results in an equation wit
Paraphin [41]
I don’t know if I’m right but I got 2/3 but you should use desmos
8 0
2 years ago
Other questions:
  • Analyzing a Graph For each graph below, identify any interval(s) where the rational function is a) positive, b) negative, c) inc
    10·1 answer
  • Melanie read 45 pages out of 100 page book her younger sister read half of a 10 page book who read a greater fraction of her boo
    7·2 answers
  • Select the correct answers.
    13·1 answer
  • Is 4/6 bigger than 5/8
    13·2 answers
  • Simplify −0.6(−6.3) answer??
    11·2 answers
  • PLEASE HELP IN ONE MINUTE
    6·1 answer
  • Estimate the MAXIMUM number of people that can be in your park at one time, before it’s too crowded. Use this information for yo
    6·1 answer
  • Find the coordinates of centroid of a triangle whose vertices have coordinates (6,2);(- 3, 4); (3,- 9).
    12·1 answer
  • I want to know what 64 take away 3 is
    15·2 answers
  • 4. find the value of ‘k’ for which 2x 3y = 4 and (k 2) x 6y = 3k 2 has a infinitely many solutions.
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!