Find the minimum value for the equation: y = x2 + 9x + 18.?

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Find the minimum value for the equation: y = x2 + 9x + 18.?

2007-05-23 04:23:26 · 4 answers · asked by James O 1 in Science & Mathematics ➔ Mathematics

4 answers

Minimum value can be determined by completing the squares
y = x^2 + 9x +18
= x^2 + 9x + 81/4 +18 - 81/4 (by adding and subracting 81/4)
= ( x + 9/4)^2 -9/4
as (x + 9/4)^2 >= 0, minimum value of y is -9/4

2007-05-23 06:46:42 · answer #1 · answered by bharat m 3 · 0⤊ 0⤋

The max / min value of a quadratic equation is -b / 2a, I think.

If that's correct, the answer is -9.

2007-05-23 11:30:45 · answer #2 · answered by Chie 5 · 0⤊ 0⤋

derivative dy/dx=2x+9 root x= -9/2 = -4.5 y=-2.25

for x=-4.5 y =-2.25

2007-05-23 11:29:04 · answer #3 · answered by maussy 7 · 1⤊ 0⤋

thats math from the 8th grade

2007-05-23 11:28:30 · answer #4 · answered by satan h 1 · 0⤊ 5⤋