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What can you add to #x^2-9x# to get a perfect square trinomial?

Answer 1

#20.25#

In a perfect square, the equation is #ax^2+bx+c#, where #abs(b) = 2asqrt(c)#. Therefore, to find #c#, plug in #a# and #b#.

#abs(b)=2asqrt(c)#

#abs(-9) = 2*1*sqrt(c)#

#9 = 2*sqrt(c)#

#4.5 = sqrt(c)#

#20.25 = c#

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Answer 2

Nathan Axel

You can add ( \frac{81}{4} ) to ( x^2 - 9x ) to get a perfect square trinomial.

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Answer 3

Nathan Axel

To get a perfect square trinomial from ( x^2 - 9x ), you can add the square of half the coefficient of the linear term. In this case, half of -9 is -4.5, and its square is 20.25. So, adding ( 20.25 ) to ( x^2 - 9x ) results in the perfect square trinomial ( (x - 4.5)^2 ).

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.