A parabola has x-axis intercepts 6 and -3, and passes through the point (1,10). Find the equation of the parabola.
1 answer:
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.
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