Question

Solving systems by substitution and elimination?

Answer 1

\[y = \frac{ 1 }{ 2 }x - 6\]
2x + 6y = 19

Answer 2

I know that answer is (11, -1/2) but I don't know how to solve it.

Answer 3

So, you know what y equals.

If you see y in another equation can't you just plug it in?

Answer 4

What I meant is that, someone told me the answer, but not how they got it. Could you explain to me how they would have got (11, -1/2) as the answer?

Answer 5

I will ask you a series of questions to help you solve this.

Question 1: what does y equal?

Answer 6

-1/2

Answer 7

Y does not equal -1/2

Read the first equation out loud and listen to what y is equal to.

Answer 8

1/2 - 6

Answer 9

If x = 25r + 25b

Then x is equal twenty-five r plus twenty-five b.

Answer 10

Okay.

Answer 11

Y = 1/2X - 6

There is no other answer. By writing y=1/2x-6 We say Y is equal to one half of x minus 6. There is nothing else that is the answer.

Answer 12

Question 2:

If x = 5,

what is y , if:

x + 10 = y

Answer 13

x plus ten.

Answer 14

This is the substitution part, if you know that x is 5.....

What is y?

Answer 15

Y would then be

x+10=y
5+10=y
15=y

Answer 16

Okay.

Answer 17

Now that's just a basic use of substitution.

Let's go back to your problem(s)

You know what y is equal to

y=1/2x-6

So then you look at the other equation

2x + 6y = 19

and say

Well if i know what y is, I can replace it with the y there.

So 2x + 6y = 19

turns into

2x + 6(1/2x - 6) = 19

Answer 18

Okay.

Answer 19

So there's the way to solve for x. Once you get a numerical answer for x, you can solve for y.

Answer 20

Okay, so what do you do afterwards?

Answer 21

Did you solve for x?

Answer 22

Well, what I meant was do i combine 2x and 1/2x?

Answer 23

You need to distribute the 6 since it was 6y and then you can proceed with solving for x from there.

Answer 24

5x - 36 = 19
5x = 55
x = 11

Replace x in one of the equations.
y = 1/2(11) - 6
y = 5.5 - 6
y = -1/2

Answer 25

And you have just solved by substitution.

Answer 26

How do you go from 2x + 6(1/2x - 6) = 19 to 5x - 36 = 19?

Answer 27

6 times 1/2x equals 3x and -6 times 6 equals -36

You may need to go back and review some algebra. It would help tremendously and I do not see another way for you to continue in mathematics without it.

Answer 28

I am going to link you to some pages. Please study them and use them and I suggest understanding these concepts before continuing your homeworkl.

Answer 29

I've done the other problems myself, its just that i didn't understand this one.

Answer 30

*I

Answer 31

Distribution property is one of the earliest rules learned in algebra.

If you can get from

2x + 6(1/2x-6) = 19
to
5x-36=19

well then there may be some necessary review:

Answer 32

http://www.worksheetworks.com/math/pre-algebra/equations-like-terms-distributive.html

Answer 33

Thank you.

Answer 34

What do you want?

Answer 35

I blocked you?

Answer 36

It doesn't say I did.

Answer 37

It doesn't say I blocked you. I have to go.

Answer 38

where?

Answer 39

Valentina?