Answer:
- 12 ft parallel to the river
- 6 ft perpendicular to the river
Step-by-step explanation:
The least fence is used when half the total fence is parallel to the river. That is, the shape of the rectangle is twice as long as it is wide.
72 = W(2W)
36 = W²
6 = W . . . . . . the width perpendicular to the river
12 = 2W . . . . the length parallel to the river
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<em>Development of this relation</em>
Let T represent the total length of the fence for some area A. Then if x is the length along the river, the width is y=(T-x)/2, and the area is ...
A = xy = x(T -x)/2
Note that the equation for area is that of a parabola with zeros at x=0 and at x=T. That is, for some fence length T, the area will be a maximum at the vertex of this parabola. That vertex is located halfway between the zeros, at ...
x = (0 +T)/2 = T/2
The corresponding area width (y) is ...
y = (T -T/2)/2 = T/4
Equivalently, the fence length T will be a minimum for some area A when x=T/2 and y=T/4. This is the result we used above.
Answer:
y= -7 and x= -1
Step-by-step explanation:
To do this, line up the variables so it looks like this...
y-6x=-1
y-3x=-4
The reason why -6x and -3y changes to negative is because that it moved to the other side of the equation.
distribute negative to the bottom equation because the two equations have the same number variable which is y...
y-6x=-1
-y+3x=4
Y cancels out and it will be left with -3x = 3.
X = -1.... plug that in to any of the two equation and you get y = -7.
Hope I helped and have a nice day!!
Answer:
D
Step-by-step explanation:
3*(-7)=(-21)
Answer:
AC = 10
Step-by-step explanation:
Two tangents drawn to a circle from the same exterior point are congruent.
AC = AB
Since AB = 10, then
AC = 10
