I would say A. becuase squares can be similar by looking alike but it doesn't matter what size, big or small.
To be a function each different x value would have a different Y value.
First one is a function, there are no repeated Y values.
The second one is a function.
Third one is not a function because it has two identical Y values with different x values.
The fourth one is a function.
To factor this fraction, you have be be aware of two special factoring formula:
a^3<span> + </span>b^3<span> = (</span>a<span> + </span>b)(a^2<span> – </span>ab<span> + </span>b^2<span>)
</span><span>(a+b)³ = a³ + 3a²b + 3ab² + b³
You can see the top part in this case is (x+y)^3, and the bottom (denominator) can be factor into (x+y)(x^2-xy+y^2)
we can cancel (x+y), so what we have left is (x+y)^2/(x^2-xy+y^2)
or (x^2+2xy+y^2)/(x^2-xy+y^2)
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The answer to this question is b