Question

solve. -2c=-18.

Answer 1

Remember what I said about isolating a? In this case, we want to isolate c. So to turn "-2c" into c, we multiply both sides by -2.

See if you can get it from there.

Answer 2

You mean divide both sides by -2.

Answer 3

-2c=-18
--- ---
-2 -2

c= 9

Answer 4

So I multiply each side (-2c and-18) by -2?

Answer 5

you divide both sides by -2

Answer 6

Now it's my turn to be corrected. Holy crap, that was stupid of me. Yes, listen to Gonzalez. -2 * -2 is equal to 4, not 1 :/

Answer 7

oh okay. So with this next one: 2/3x=6. would that be the same? not the answer, just how to do it.

Answer 8

yes you would have to divide both sides by 2/3

Answer 9

ok

Answer 10

Because dividing things by a fraction hurts my brain, I'll contribute that you can also invert a fraction and multiply instead.

Answer 11

would the answer be x=12?

Answer 12

What Sacapuntus said is probably easier. In case you don't know, inversion means that x/y is now y/x. The top number becomes the bottom number, and vice versa.

So, 2/3 becomes 3/2. Multiplying 2/3 by 3/2 (Or indeed, any positive fraction by it's inverse) will always get you 1.

So 2/3x * 3/2 = 6 * 3/2.

6 * 3/2 is 9, so our answer is 9.

Answer 13

I skipped a step there: 2/3 x * 3/2 = x. And we want to isolate x. So x = 9.

Answer 14

If you want to know if an answer is right, just try to put it in the equation. If you want to know if x is 12, then just put in 12 for x and see if it works. (It doesn't)

Answer 15

:( ok

Answer 16

What about 6.5=-3+n?

Answer 17

Okay, we want to isolate n. So that means we need to get rid of the "-3" from the right side of our equation. If we didn't have that, it'd just be n.

So how can we get rid of a -3?

Answer 18

I would close the question and put the other questions in but your here now so might as well ask away.

Answer 19

Yeah, this is better :) Feel free to ask here.

Answer 20

I don't know, I'm clueless. I'm really bad at math so I do apologize if I frustrate you haha.

Answer 21

Okay, no problem, that just means I need to give you an overview of what you're actually trying to do. Sit tight :)

Answer 22

Alrighty

Answer 23

to get rid of a negative number you have to add

Answer 24

so you would add 3 to both sides to get the answer for n

Answer 25

So would that be 9.5?

Answer 26

yes

Answer 27

Yay! Okay so what about x/4=12/6. I really don't like these.

Answer 28

To understand how to solve these equations, you need to understand the idea of mathematical opposites.

Addition and subtraction are opposites. Think of what would happen if you had the number 7, then you added 3, then took away 3. You can do this right now. You'll end up with the same number. 7 + 3 = 10. 10 - 3 = 7. Basically, subtraction is literally reverse addition.

Multiplication and division are also opposites. 3 x 3 is 9, and then 9 / 3 is 3 again. Division is just multiplication going the other way.

So now, how do we translate this to algebra?

Well, in order to "solve" an algebraic equation, we want it to look like this:

x = A number.

Our x should be alone on one side, and we should have a number like 2 or 5 or -6 on the other side.

So, how would we turn, say, "x + 2" into x again?

That's where the concept of opposites comes into play! The opposite of +2 is -2. Any number, if you add 2 to it, and then take away 2, you get the original number back.

So let's say we have "x + 2 = 4."

We want it to say "x = 2". That's our answer.

So what we do is, we subtract both sides by two, to reverse our "+2." So what we have here is:

"x + 2 - 2 = 4 - 2."

x + 2 - 2 is equal to x, and 4 - 2 is equal to 2.

If you're still not understanding (Which you might not, it's difficult to do this without showing it visually) I highly recommend this video: https://www.khanacademy.org/math/algebra/solving-linear-equations-and-inequalities/equations_beginner/v/simple-equations

Answer 29

If that video helps you, just keep going. Algebra is hard to grasp at first.

Answer 30

Thank you!