Simplify the expression.
1 answer:
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Answer:
y=-1/2 x^2+3/2 x+9
Step-by-step explanation:
The equation of parabola is:
y=ax^2+bx+c
We know that parabola has three poibts
(6,0),(-3,0) and (1,10).
So we put these three points in equation:
a*36+b*6+c=0......(1)
a*9-3b+c=0........(2)
a+b+c=10........(3)
(1)-(2) we have:
27a+9b=0.....(4)
(2)-(3) we have:
8a-4b=-10.....(5)
4(4)+9(5) we got:
180a=-90
a=-1/2
From (4) we got: b=27/18=3/2
From (3) we got: c=10+1/2-3/2=9
So equation is:
y=-1/2 x^2+3/2 x+9
You can see the picture of parabola through three points.
The expected value is
The standard deviation is the square root of the variance, which is
where
so that
making the standard deviation