8(x - 6) = 4x
Distribute.
8x - 48 = 4x
Subtract 8x from both sides.
8x -8x - 48 =4x -8x
Now you have...
-48 = -4x
Divide -4 by both sides.
-48/-4 = -4x/-4
12 = x
The number is 12.
We apply the Pythagorean theorem twice and obtain:
12 ^ 2 = x ^ 2 + (15-d) ^ 2
9 ^ 2 = x ^ 2 + d ^ 2
We observe that it is a system of two equations with two unknowns whose solutions are:
(x, d) = (-36/5, 27/5)
(x, d) = (36/5, 27/5)
We ignore the negative solution, therefore, the solution is:
(x, d) = (36/5, 27/5)
Answer:
The length of the new fence is:
x = 36/5 meters
1 m = 100 cm
1 m^3 = 1^6 cm^3
so 1 cm^3 = 10^-6 m^3
and 1 L = 1000 cm^3 = 10^-3 m^3