Answer:
8-x meters
Step-by-step explanation:
Both 64 and x^2 are perfect squares, since 64=(8)^2 and x^2=(x)^2.
Additionally, 16x is twice the product of the roots of 64 and x^2, since 16x=2(8)(x).
So we can use h the square of a difference pattern to factor:
a^2-2(a)(b)+b^2=(a-b)^2
In this case, a=8 and b=x:
(8)^2-2(8)(x)+(x)^2=(8-x)^2
In conclusion...
64-16x+x^2=(8-x)^2
So the side length of the square is 8-x meters.
