D=rt
r=(boatrate+riverrate)=(x+2)mph
d=528ft=528/5280mi=1/10mi
t=1/3hr
remember to keep the same units
so
1/10=(x+2)(1/3)
times both sides by 3
3/10=x+2
minus 2 or 20/10
-17/10=x
-1.7=x
it would be going -1.7mph (means going backwards)
We know that
the equation of the parabola is of the form
y=ax²+bx+c
in this problem
y=1/4x²−x+3
where
a=1/4
b=-1
c=3
the coordinates of the focus are
(-b/2a,(1-D)/4a)
where D is the discriminant b²-4ac
D=(-1)²-4*(1/4)*3-----> D=1-3---> D=-2
therefore
x coordinate of the focus
-b/2a----> 1/[2*(-1/4)]----> 2
y coordinate of the focus
(1-D)/4a------> (1+2)/(4/4)---> 3
the coordinates of the focus are (2,3)
Answer: 10 units²
Step-by-step explanation:
We can divide the shape along the y-axis to get 2 separate triangles. If we find the area of each and add them up, we can get the total area of the figure.
We can get each triangle's area using the formula 
<h3>Left Triangle</h3>
base length - 4 units
height - 4 units


<h3>Right Triangle</h3>
base length - 2 units
height - 2 units



Total = 8 units² + 2 units² = 10 units²