Need help understanding solving 2(2x +1) - 3(x - 1) = 8  TOPIC_SOLVED

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Need help understanding solving 2(2x +1) - 3(x - 1) = 8

Postby kiwiguy86 on Mon May 13, 2013 7:54 pm

Solve the following equation. 2(2x +1) - 3(x - 1) = 8

After a long absence from algebra (and maths in general) I can't understand why X=3 - can someone please help shed light on the workings of this equation. many thanks
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Re: Need help understanding solving 2(2x +1) - 3(x - 1) = 8

Postby kiwiguy86 on Mon May 13, 2013 8:19 pm

Actually I think I've just wrapped my mind around it - can someone confirm


2(2x +1) - 3(x - 1) = 8
first expand brackets
4x +2 -3x +3 = 8 (multiplying negative by a negative creates a positive and multiplying a negative by a positive creates a positive)
Second group everything together
x + 5 = 8 ( 4x-3x = x and 2+3 = 5)
third subtract 5 from both sides to reveal x
x=3

:clap:

. . . . only taken me 2 days to work this one out in my head, please tell me I'm approaching it in the correct fashion.
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Re: Need help understanding solving 2(2x +1) - 3(x - 1) = 8

Postby little_dragon on Mon May 13, 2013 10:16 pm

yeh U did it rite!
U can check it by plugging it back in:
2(2*3+1)-3(3-1)=2(6+1)-3(2)=2(7)-6=14-6=8
it checks so its rite!
:wave:
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Re: Need help understanding solving 2(2x +1) - 3(x - 1) = 8  TOPIC_SOLVED

Postby kiwiguy86 on Tue May 14, 2013 4:41 am

:mrgreen: Woooo!!!! Such a relief to know that this stuff is still in there somewhere - thanks for confirming my thought process
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