Question

Solve this equation in substituion method
3x+(-3x+9)

Answer 1

Hey winter

Answer 2

hi

Answer 3

Let's focus on the math, OK?
What does the substitution method have to do with this problem? Was there another equation that you could use as a substitution?

Answer 4

Equal values method

Answer 5

Could you explain that?
What is the goal of this problem?

Answer 6

Substitution or equal values ?

Answer 7

I'm asking you. Hard to "solve" a problem until we know where we're going.
What is the goal of this problem you've posted?

Answer 8

To solve it and finding the answer

Answer 9

I think the first thing is to distribute ?

Answer 10

Try removing the parentheses. Type out what you get by doing that. No, there's nothing to distribute here (other than the + sign).

Answer 11

3x+-3x+9

Answer 12

Must combine +-. Which sign do you mean?

Answer 13

But don't you need the parentheses for substitution

Answer 14

both

Answer 15

So u mean plus a negative

Answer 16

its -3 not subtracting

Answer 17

Really, substitution has nothing to do with this problem, unless you've copied it incorrectly.

Answer 18

So your 3x - 3x + 9 = ?

Answer 19

In the question it says solve this system algebraically using the substiution method

Answer 20

Screen shot and send plz

Answer 21

You have listed only ONE equation. Note that "a system of linear equations" involves TWO linear equations. Where's the other one?

Answer 22

y=3x and y= -3x+9

Answer 23

Here you presented only 1 equation, whereas you started with 2 equations. That's where the confusion started.

How would you use substitution to solve this system of linear equations?

Answer 24

plug in 3x into the second equation where y is

Answer 25

So it would be -3x+9(3x) ??

Answer 26

All right, then. We then get 3x=-3x+9. No parentheses, notice?

How would you solve this? First step?

Answer 27

oh

Answer 28

subtract -3x on both sides right ?

Answer 29

Why subtract? What's your goal here?

Answer 30

Its the inverse operation of adding

Answer 31

Your goal is the inverse operation of adding? ???

Answer 32

no to solve the equation

Answer 33

Why would you add or subtract something to both sides of this equation?

What are y ou trying to do?

3x=-3x+9

What next, and why?

Answer 34

Add both sides ??

Answer 35

your confusing me

Answer 36

Yes

Answer 37

@mathmale is here you are in good hands

Answer 38

oh I got it I already solved it but I don't know if my answer is right ?

Answer 39

x=3/2

Answer 40

mathmale Medals 0
Look: You have 3x=-3x+9.
Your goal is to solve this equation for x.
You have x on both sides of this equation. Not good.
How do you move the -3x on the right side over to the left side?

Show your work.

3x=-3x+9
What next?

Answer 41

y=9/2

Answer 42

Is that right ??

Answer 43

Explain. My question for you, Winter, was how could you get rid of that -3x on the right side and have all x terms on the left side?

Answer 44

Screen shot and send plz

Answer 45

If I gave you -3x, what operation, involving what quantity, would give you a zero?

Answer 46

Screen shot and send plz

Answer 47

In different words: You want to group ALL x terms on the left side.
That's what we're trying to do here.

Answer 48

so my answers are wrong?

Answer 49

Please follow my directions.

Answer 50

okay

Answer 51

You have 3x on the left side of your equation and you have -3x on the right side.
Your task is to consolidate the x terms on the LEFT side. I asked you before: Suppose I gave you -3x...What math operation would result in that -3x becoming zero?

Answer 52

subtracting ?

Answer 53

+ and - are opposite operations. If I give you -3x, you could turn that into a zero by adding 3x.

Do that now, please. -3x+3x=?

Answer 54

3x
-3x
-----
?

Answer 55

-3x+3x=0

Answer 56

like terms

Answer 57

Yes. That's how you get rid of the -3x on the right side.
Now the entire equation is 3x=-3x+9. Solve for x.

Move that -3x on the right side to the left side of this equation.
You now know how to do this.

Answer 58

3x = -3x + 9

3x = 9 + -3x

3x + 3x = 9 + -3x + 3x

Combine like terms: 3x + 3x = 6x
6x = 9 + -3x + 3x

Combine like terms: -3x + 3x = 0
6x = 9 + 0
6x = 9

Divide each side by '6'.
x = 1.5

Answer 59

Very nice. Any questions?

Answer 60

no thank you so much

Answer 61

I don't plug in for y??