find the value of c that completes the square
I don't understand why the answer is 121/256
z^2+ 11/8 z + c
Thanks!
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Remark:
( a + b )² = a² + 2 ∙ a ∙ b + b²
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In this case:
( z + b )² = z² + 2 ∙ z ∙ b + b²
( z + b )² = z² + 11 z / 8 + b²
2 ∙ z ∙ b = 11 z / 8
Divide both sides by z
2 b = 11 / 8
Divide both sides by 2
b = 11 / 16
b² = ( 11 / 16 )²
b² = 11² / 16 ²
b² = 121 / 256
( z + 11 / 16 )² = z² + 11 z / 8 + 121 / 256