I think the answer is 10% and 90%
We know that the points at which the parabola intersects the x axis are
(-5,0) and (1,0)
So the extent between these two points would be the base of the triangle
lets find the length of the base using the distance formula
![\sqrt{[(-5-1)^{2}+(0-0)^{2} ]}](https://tex.z-dn.net/?f=%20%5Csqrt%7B%5B%28-5-1%29%5E%7B2%7D%2B%280-0%29%5E%7B2%7D%20%5D%7D%20%20)
the base b=6
We will get the height of the triangle when we put x=0 in the equation
y=a(0+5)(0-1)
y=-5a
so height = -5a (we take +5a since it is the height)
We know that the area of the triangle =
× 6 × (5a) = 12
15a=12
a= 
An angle is any two rays that share an endpoint. the reason that last part is important is becasue they could be one ray that starts in seatlle and one ray starting over in new york. these would not for an angle. if i confused you let me know and ill try to clarify.
-2(4x-1)=5+7
(4x-1)=12/-2
4x=-6+1
x=-5/4