for ln(x), the base is e, the natural base (aprox equal to 2.718281828454590...) or 
for log(x), if no base is stated, assume base 10 or 
Answer:
Step-by-step explanation:
The answer is: " 5/2 ; or, write as: "2 ½ " ; or, write as: "2.5" .
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15/ (3x - 6) ;
Substitute "4" for "x" ; and solve:
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Note: (3x -6) = 3(4) - 6 = 12 - 6 = 6 ;
Rewrite the expression:
15/6 = (15 ÷ 3) / (6 ÷ 3) = 5/2 ; or, write as: "2 <span>½ " ; or, write as: "2.5" .
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A = 2
b = 2
c = -4
"a" is greater than zero so the vertex is a minimum point and the graph is concave up.
The (x,y) point of the vertex is usually designated by the letters (h, k)
The "x" position (or "h") is calculated with this formula:
h = -b / 2a
h = -2 / 4
h = -1 / 2
"k" is calculated with this equation:
k = ah^2 + bh +c
k =(2*-1 / 2 * -1 / 2) + (2 * -1 / 2) + -4
k = (1 / 2) - 1 -4
k = -4.5
so the vertex is at point (-.5, -4.5)
Source:
http://www.1728.org/quadr3.htm