Answer:
x = 15 ft
y = 15 ft
A(max) = 225 ft²
Step-by-step explanation:
Let call "x " and " y " sides of the rectangle x (side paralll to the northern boundary, then:
A(r) = x*y and 4*x + 2*2*y = 120 or 4*x + 4*y = 120
4*x + 4*y = 120 ⇒ x + y = 30 ⇒ y = 30 - x
Area of the garden as a function of x is:
A(x) = x* ( 30 - x ) ⇒ A(x) = 30*x - x²
Taking derivatives on both sides of the equation
A´(x) = 30 - 2*x
A´(x) = 0 ⇒ 30 - 2*x = 0
2*x = 30
x = 30/2
x = 15 ft
And y = ( 30 - x )
y = 15 ft
A(max) = 15*15
A(max) = 225 ft²
Siince 2nd equation is already equal a, subsitute b-2 for a in the other equation
b-2-3b=28
-2-2b=28
add 2 to both sides
-2b=30
divide both sides by -2
b=-15
sub back
a=b-2
a=-15-2
a=-17
(a,b)
(-17,-15)
3rd choice
A: Speed is Independent as it can be anything with no restrictions. Gas mileage is dependent as it relies on the value of speed for its value to be decided.
B: The first letter of speed is "S" so it can represent the variable. The first letter of mileage is "M" so the variable can be represented by that letter. It really can be any letter.
C: no context
D: no context
If y=logv32 1 answer is 1.506505032