The side length is 12 - -3 = 15 so the area is 15 squared = 225.
So hmmm notice the picture below
thus

solve for "h"
Erm
x+y=6
xy=12
x+y=6
y=6-x
sub back
xy=12
x(6-x)=12
6x-x^2=12
x^2-6x=-12
x^2-6x+12=0
quadratic formula
for
ax²+bx+c=0

for
x²-6x+12=0
a=1
b=-6
c=12
and remember that √-1=i






x=3+/-i√3
the numbers are 3+i√3 and 3-i√3
no real numbers tho
To find the future value the formula is
A=p e^rt
A future value?
P present value 8906.54
R interest rate 0.06
T time 9 years
E constant
A=8,906.54×e^(0.06×9)
A=15,283.68
To find the interest earned the formula is
I=A-p
I=15,283.68−8,906.54
I=6,377.14