Thinking about the graph of y, the rate of change is zero whenever there is an extremum.
First, differentiate y.

Next, find the zeros of y' by factoring.

Now, we substitute these x-values into the
original equation to find the coordinates.
When the son is 8, the father is five times that so 8*5 = 40, difference between their ages is 32
twice as old 32*2 = 64
The father will be 64.
Answer: 4.24264069
Step-by-step explanation: I think you mean the square root?
Area=1/2 times base times height
note:bh=base times height
a=1/2bh
b=width
h=-4+2w
h=2w-4
subsitute
a=1/2w(2w-4)
a=1/2(2s^2-4w)
a=w^2-2w
a=63
63=w^2-2w
subtract 63 from both sdies
0=w^2-2w-63
factor
find what 2 numbers multiply to get -63 and add to get -2
the numbers are -9 and 7
so
0=(w-9)(w+7)
if xy=0 then x and/or y=0
so
w-9=0
w+7=0
solve each
w-9=0
add 9 to both sdies
w=9
w+7=0
subtract 7 from both sides
w=-7
width cannot be negative so this can be discarded
width=9
subsitute
l=2w-4
l=2(9)-4
l=18-4
l=14
legnth=14 in
width/base=9 in