<PRE><B>Question 192326</B>
find a value for K that will make 4x^2 + 6.4x + K a perfect square. Describe --the procedure 
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A perfect square would look like this: a^2 + 2ab + b^2
In your problem a^2 = 4x^2, so a = 2x
In your problem 2ab = 6.4x 
So, 2(2x)b = 6.4x
So, 4b = 6.4
So, b = 1.6
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In your equation b^2 = K
So, K = (1.6)^2 = 2.56
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Cheers,
Stan H.</PRE>