Question

Solve the system.

y = 4x + 12 and y = -2x + 6

Answer 1

pick your method, substitution or elimination?

Answer 2

substitution looks ok since it only 2 equations and 2 variables and you are already solved for y.

Answer 3

4x + 12 = -2x + 6

Answer 4

-1,3 ?

Answer 5

Did you mean to say that, x = -1 and y = 3 @IllGiveYouMyAll ?

Answer 6

Yes, is that correct? @mathslover

Answer 7

x = -1 seems okay. But, y = 3 does not ...

Answer 8

How did you get to the above conclusion ?

Answer 9

I guessed. It's so confusing... Ugh.

Answer 10

See, is it clear to you , that : 4x + 12 = -2x + 6 ?

Answer 11

Well yes, but once i start solving it i seem to mess up.

Answer 12

No problem. We're here to help you with that.

Okay. Let's start solving it.

First of all,

\(\boxed{4x + 12 = -2x + 6}\)

Now, add \(\bf{2x}\) both sides.

\(\implies 4x + 12 + \underline{2x} = -2x + \underline {2x} + 6\)

[Notice the underlined "2x" there]

Answer 13

Now, can you tell me, what is :

4x + 12 + 2x ?

Answer 14

6x + 12?

Answer 15

Good :) . Now, similarly solve for : -2x + 2x + 6

Answer 16

6?

Answer 17

Very good !

So, you have now : 6x + 12 = -6

Can you solve for "x" from the above equation now?

Answer 18

3?

Answer 19

No , no! A little bit mistake.

6x + 12 = -6

Add 6 both sides

6x + 12 + 6 = -6 + 6

6x + 18 = 0

Subtract 18 both sides

6x + 18 - 18 = 0 - 18

6x = -18

Divide 6 both sides

\(\cfrac{6x}{6} = \cfrac{-18}{6} \)

x = -3

Answer 20

Oh, oh i see. I never know if when you multiply if it will be negative or positive.

Answer 21

Okay, now you have x = -3.

You had in first, y = 4x + 12

Answer 22

Put the value of x = -3 in : y = 4x + 12

and solve for y

Answer 23

0?

Answer 24

Yes, but wait... a mistake there.

Answer 25

I did a mistake there . Sorry, : 6x + 12 = 6 [Not -6]

Answer 26

i.e. : \(6x + 12 = 6\)

Sorry for the blunder.

Answer 27

Though, process will be exactly same.

6x + 12 = 6

Subtract 12 both sides

6x + 12 -12 = 6 - 12

6x = -6

x = -1

Answer 28

y = 4x + 12 [Given]

y = 4(-1) + 12

Now solve for y.

Answer 29

So the answer is (-1,-3)?

Answer 30

No no!

y = 4(-1) + 12

y = -4 + 12


y = ?

Answer 31

8!

Answer 32

Yep, good.

So, y = 8 and the solution is : (-1,8)

Answer 33

Thank you SO much! c:

Answer 34

You're very welcome :)

Answer 35

And also,
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