Question

Solve for x.

7 - (2x + 11) + 3(3 - x) = 20

Answer 1

7/5
-3
-4

Answer 2

First distribute the - through the first parens and the 3 through the second parens. Then combine like terms.

Answer 3

ok

Answer 4

does that mean you're good to go?

Answer 5

Wokay!

This is similar stuff -

the expression has two parts - solve each separately first.

7 -(2x+11) = remember the last one? ;) Try try c'mon!

Answer 6

yup

Answer 7

2x-4

Answer 8

almost there! minus sign would attach a '-' beside 'that '2x' as well - right?
so what does it become?

Answer 9

2x+4

Answer 10

umm :(

no change to that '4' --> because 7 - 11 = '-4' --> you did that alright.

don't guess, try to think :)

Answer 11

what change to that sign beside '2x'?

Answer 12

what do u mean

Answer 13

what is 'minus' times 2x?

Answer 14

-2x

Answer 15

yeah!
so -2x added to '-4' --> what's that?

Answer 16

-2x+-4

Answer 17

Okay - and what happens when + and - adjacent - they make a 'minus' right?

Answer 18

So you can write that simply as -2x-4 right?

Answer 19

Easiest to distribute all terms first, then combine the terms afterwards.

7-2x-11+9-3x=20

Then combine.

Answer 20

yeah. @nbouscal - only if this kid knew how to 'rip open' brackets -.- No worries, we 'll get to that, Tyler!

Answer 21

ok this really anoyying

Answer 22

Now for the second part of the LHS --> 3 times (3-x)

so multiply each term in the bracket by 3 now - whaddya get?

Answer 23

im under the impreesion u guys are insulting me

Answer 24

9-3x

Answer 25

Lol, yeah annoying right now - better get annoyed for a few more minutes, rather than getting during your tests.


And no - we are not insulting you - or we would not have taken the pain of toiling with you in your questions... We just want to make sure that you are able to understand this stuff.
not everyone knows math, and there is nothing to feel ashamed about it. With a bit of cool thinking, you can master this stuff!

Answer 26

Yeah yeah!! 9-3x! brilliant!

now the two parts are:
-2x-4 added to 9 -3x --> so what does that make?

Answer 27

2x-4+9-3x

Answer 28

yup!
now add or subtract (according to sign) like terms - like '2x' and '-3x' for one, and '-4' and '9' for the other.

Answer 29

-x+5

Answer 30

wonderful!!!! great going!!

now now so the LHS is "-x+5" and the RHS is "20"

so, -x+5=20

can you solve^ this equation?

Answer 31

yes

Answer 32

so what is your answer?

Answer 33

-4

Answer 34

Nmm nmm.. Nope :(

-x+5 = 20

add '-5' to both sides what do you get?

Answer 35

-3?

Answer 36

:(
Subtracting '5' from both sides:

-x + 5 -5 = 20 -5


what does this simplify to?

Answer 37

x=15

Answer 38

You guys lost a minus sign a ways back, it was -2x, not positive 2x

Answer 39

Hmm yeah *facepalm*! thanks @nbouscal

Answer 40

I foolishly missed what Tyler typed in there too :/

So, it's:
you add '-2x' and '3x' actually --> that is '-5x'

so your equation actually is-->

-5x+5=20

now divide the whole equation by '5'.
\[\frac{-5x}{5} + \frac 5 5 = \frac{20} 5\]

Answer 41

what do you get?

Answer 42

-x+1=4

Answer 43

great!!
now subtract '1' from both sides.

Answer 44

x=3

Answer 45

lol no!
-x=3 actually --> noticed?

Answer 46

x=-3

Answer 47

Yeah!! right now. Good. - seems tough? isn't. just need to practice a couple more I guess.

Answer 48

no not now

Answer 49

Yeah, later maybe.