ThisShouldFeelLikeFire
How exactly do I solve this equation?
x2 - 12x = -36
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kevsturge
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\[x^2-12x+36=0\] now solve the quadratic
kevsturge
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gives x=6 can yuo see why
precal
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you can use the quadratic formula
or you can factor it
you can also, look at its graph and see where it crosses the x axis
kevsturge
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here yuo can factor the eqn, Do you know how to do this?
ThisShouldFeelLikeFire
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I don't understand how you got x = 6...
precal
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|dw:1338677027789:dw|
precal
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|dw:1338677062779:dw|
ThisShouldFeelLikeFire
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I'm sorry... I'm so confused. /:
ThisShouldFeelLikeFire
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Took me a little bit :P Thank you both a ton!!
kevsturge
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if you factorise the equation you get
(x-6)(x-6)
so when (x-6)=0 x=6
Do you see
kevsturge
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Here is how I practice factorising write the factorised end point i.e. (x+3)x+4)
and expand the brackets to give\[x^2+4x+3x+12 \rightarrow x^2+7x+12\]
now |I take \[x^2+7x+12\] and work backwards because I know it will definitely factorise
precal
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|dw:1338678477379:dw|
precal
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|dw:1338678551861:dw|
kevsturge
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wow that's the hard way! but it does always work. Try to factorise it before going through all this stress
precal
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just presenting multiple ways to solve it. Quadratic formula works 100% of the time, factoring does not
kevsturge
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that's what I said :P