Answer:
Step-by-step explanation:
Four consecutive counting numbers would look like this
x
x + 1
x + 2
x + 3
Do you see that these numbers are 1 larger than the one before it. So if x is 20 the numbers would be 20 21 22 23
Now take the 4 general numbers and add them
x + x + 1 + x+2 + x + 3
4x + 6
Two will go into 4x to give 4x/2 = 2x
Two will go into 6 to give 6/2 = 3
Always happens. There are no exceptions. Try x = 20 again
20 + 21 + 22 + 23 = 86
Can this number be divided by 2? Yes it can 86/2 = 43
Answer:
x = 28 m
y = 14 m
A(max) = 392 m²
Step-by-step explanation:
Rectangular garden A (r ) = x * y
Let´s call x the side of the rectangle to be constructed with a rock wall, then only one x side of the rectangle will be fencing with wire.
the perimeter of the rectangle is p = 2*x + 2*y ( but in this particular case only one side x will be fencing with wire
56 = x + 2*y 56 - 2*y = x
A(r) = ( 56 - 2*y ) * y
A(y ) = 56*y - 2*y²
Tacking derivatives on both sides of the equation we get:
A´(y ) = 56 - 4 * y A´(y) = 0 56 - 4*y = 0 4*y = 56
y = 14 m
and x = 56 - 2*y = 56 - 28 = 28 m
Then dimensions of the garden:
x = 28 m
y = 14 m
A(max) = 392 m²
How do we know that the area we found is a local maximum??
We find the second derivative
A´´(y) = - 4 A´´(y) < 0 then the function A(y) has a local maximum at y = 14 m
Answer:
l think 10
Step-by-step explanation:
a=?
b=20
c=30
30-20=10