#Geometry

55 messages · Page 1 of 1 (latest)

red prairie
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How can you tell if you or subtract it?

untold oceanBOT
red prairie
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So for example 10x + 10 = 90

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10x +10 = 90
10x = 80
x= 8

red prairie
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why is that?

earnest sable
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it subtracts because you need to subtract both sides by 10

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so you can isolate x

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10x + 10 = 90
-- 10 = - 10

this becomes:

10x = 90 - 10
10x = 80

divide both sides by 10

x = 8

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gets mo ba

red prairie
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nop

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combine like terms right?

earnest sable
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yeah you should combine like terms

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but before you could combine them, place the like terms on one side

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if you move that 10 to the other side, it becomes negative

red prairie
earnest sable
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yes

red prairie
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if you move it to the right

earnest sable
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it becomes a negative

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yes

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right

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you subtract both sides by 10

red prairie
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so the sign doesnt matter? its just subtract?

earnest sable
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yes you just subtract

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for instance

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10x - 10 = 90

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how would you do this

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solve for x for this example

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you try it

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now the 10 is negative

red prairie
earnest sable
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that's wrong

red prairie
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??

earnest sable
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before it was
10x + 10 = 90

red prairie
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10x = 80 x = 8

earnest sable
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now it's
10x - 10 = 90

red prairie
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yeh then you subtract 10 from 90

earnest sable
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no

red prairie
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oh

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mb

earnest sable
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you subtract -10 both sides

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subtracting a negative is just addition

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-(-10)

red prairie
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so 10 + 90 ?

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wait wut

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x = 10?

earnest sable
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yes

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-(-10) = +10

red prairie
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so basically if its a subtraction sign you add, and if its an addition sign then it subtracts?

earnest sable
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yes

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you just follow it

earnest sable
red prairie
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tyyyy

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i get it now 🙂

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