A = (12 x 8 x 3) + (1/2 x 8 x 6.9) + (1/2 x 8 x 7 x 3)
A = 288 + 27.6 + 84
A = 399.6 m²
<span>Simplify ((1/x)-(1/y))/((1/x)+(1/y))</span>
y-x
______
y+x
For this case we have the following system of equations:

We multiply the second equation by -5:

Now we add the equations:

We find the value of the variable "y":

THE solution is: (-6, -3)
Answer:
(-6, -3)
1/2 because you can simplify 4/8 and do 4 divided by 4 and 8 divided by 4 which is 1/2