Any help on this would be appreciated... write $\displaystyle 4x^2 - 24x + 27 $ in the form $\displaystyle a(x-b)^2+c $ i have thought about factorising but it wants the $\displaystyle + c $ which just confuses me thanks
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Originally Posted by RubbishAtMaths Any help on this would be appreciated... write $\displaystyle 4x^2 - 24x + 27 $ in the form $\displaystyle a(x-b)^2+c $ i have thought about factorising but it wants the $\displaystyle + c $ which just confuses me thanks $\displaystyle y=4x^2-24x+27$ $\displaystyle y-27=4x^2-24x$ $\displaystyle y-27=4(x^2-6x) $ $\displaystyle y-27=4(x^2-6x+9-9)$ $\displaystyle y-27=4(x-3)^2-4(9)$ $\displaystyle y=4(x-3)^2-9$ Edit: Moo beat me to it!
Hello, Originally Posted by RubbishAtMaths Any help on this would be appreciated... write $\displaystyle 4x^2 - 24x + 27 $ in the form $\displaystyle a(x-b)^2+c $ i have thought about factorising but it wants the $\displaystyle + c $ which just confuses me thanks $\displaystyle 4x^2-24x+27=4(x^2-6x)+27=4[(x-3)^2-3^2]+27$ $\displaystyle =4(x-3)^2-4 \cdot 3^2+27=4(x-3)^2-9$
how do you go about completing the square? *thanks moo!
Originally Posted by RubbishAtMaths how do you go about completing the square? *thanks moo! \
Last edited by TheMasterMind; Jan 8th 2009 at 01:39 PM. Reason: wish to delete
i understand most of it just not the bit i have pointed out Originally Posted by TheMasterMind $\displaystyle y=4x^2-24x+27$ $\displaystyle y-27=4x^2-24x$ $\displaystyle y-27=4(x^2-6x) $ $\displaystyle y-27=4(x^2-6x+9-9)$ $\displaystyle y-27=4(x-3)^2-4(9)$ I dont Understand what u did with the -27 and how u got the -4(9)??? thanks $\displaystyle y=4(x-3)^2-9$ Edit: Moo beat me to it!
Originally Posted by adeshSB i understand most of it just not the bit i have pointed out $\displaystyle y-27=4(x-3)^2-9(4)$ $\displaystyle y-27=4(x-3)^2-36$ $\displaystyle y=4(x-3)^2-36+27$ $\displaystyle y=4(x-3)^2-9$
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