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#2 2005-06-04 21:01:32
- MathsIsFun
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Re: Linear Equations
Easy (I think) 
This kind of problem just needs playing with until it neatens up.
Lets have a go:
Start with: 3(x+1) + 5x+3/2 = -2
Expand the brackets: 3x+3 + 5x+3/2 = -2
Combine the x's: 3x+5x + 3 +3/2 = -2
then add: 8x + 3 +3/2 = -2
Now add 3 and 3/2: 8x + 9/2 = -2
Now subtract 9/2 from both sides: 8x + 9/2 -9/2 = -2 -9/2
Simplify: 8x = -2 -9/2
Combine -2 and -9/2: 8x = -13/2
Divide both sides by 8: 8x/8 = (-13/2)/8
Simplify: x = -13/16 DONE
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman
#4 2005-06-04 21:08:00
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Re: Linear Equations
LOL ... OK start again (I will work it out and post in a few minutes)
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman
#5 2005-06-04 21:12:36
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Re: Linear Equations
Start: 3(x+1) + (5x+3)/2 = -2
Expand brackets: 3x+3 + (5/2)x + 3/2 = -2
Multiply both sides by 2 (makes it easier not to have the fractions): 6x+6 + 5x + 3 = -4
Combine the x's: 11x+6 + 3 = -4
Combine 6 and 3: 11x+9 = -4
Subtract 9 from both sides: 11x+9-9 = -4-9
Simplify: 11x = -13
Divide both sides by 11: 11x/11 = -13/11
Simplify: x = -13/11
Now, let me check ...
3(-13/11 +1) + (5 * (-13/11)+3)/2 = -2
3(-2/11) + (-65/11 + 33/11)/2 = -2
-6/11 + (-32/11)/2 = -2
-6/11 - 16/11 = -2
-22/11 = -2
-2 = -2
YAY!
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman
#8 2005-06-04 21:25:07
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Re: Linear Equations
Well, we might both be wrong ....
Nah!
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman