Question

2x-9+7x-27=90
Can someone please help explain how to work out this problem step-by-step, solving for x?

Answer 1

Mmk, so, to solve for x, we need to get x alone; by itself. Are you familiar with reverse pemdas?

Answer 2

First time I have ever heard of it actually, does it have to doing with everything in reverse? Such as addition and subtraction from right to left?

Answer 3

Exactly

Answer 4

What math are you in, out of curiosity?

Answer 5

Geometry, this is part of a larger question to do with angles, but its the equation itself I am confused with.

Answer 6

We use reverse pemdas to change an equation so we may get what we want; make it easy. Oh, mmk.

Answer 7

Mmk, so, first off we may simplify that problem. Do you see how?

Answer 8

2x-9+7x-27=90
So do we take the -27 and subtract it from both sides of the equation?
i.e.
2x-9+7x-27=90
+27 -27

Answer 9

Exactly, you get it. That is perfectly great. Personally, I would subtract the -9 and -27 first, then do it, but it is up to you. We will have to do that eventually, though.

Answer 10

And add the 2x and 7x.

Answer 11

But yeah, you got it man. Now, solve it while I do it aswell, and see what we get; see if it is the same.

Answer 12

Alrighty

Answer 13

What did you get?

Answer 14

If you need some more help, feel free to say so.

Answer 15

Just a sec, I'm writing it out by hand. Showing work on this assignment is key, apparently. as with all math.

Answer 16

No problem.

Answer 17

I got 9.1
Something tells me that's not right.

Answer 18

I got 14. So, lets work this out.

Answer 19

2x-9+7x-27=90

Answer 20

Alright, so i ended up starting with taking the 27 off both sides of the equation like before, but what would you recommend starting with?

Answer 21

Personally, combining like terms

Answer 22

Combining the -27 and -9 and 2x and 7x.

Answer 23

It will result in this: 9x-36=90

Answer 24

From then, what do?

Answer 25

What do you think we should do, is what I mean to ask.

Answer 26

Work the 36 out of the equation, correct?

Answer 27

Correct. And what new equation will we get once you do so?

Answer 28

If I did everything properly, 9x=126.

Answer 29

Yup, now divide the 9 over, and we should get the right answer

Answer 30

9/26= 14
Well dang on. Awesome.

Answer 31

So, when you did it your way, I'm assuming that after you added +27 on both sides, you accidentally added a -9 to both sides, instead of a +9.

Answer 32

Haha. Yep. That's exactly what I had done.

Answer 33

Yeah, it still happens to me lol. When your answer blows up on you, either you don't know what you're doing at all, or there was a minor error. If you have any more questions, feel free to ask.

Answer 34

Alright, thanks. I have one more like question, and if that does the same, I'll ask. Thanks for the help man.

Answer 35

No problem. Kill that question man; you got it.