Question

Thomas says that you can take the square root of each side of an equation. Therefore, he feels that (x+5)^2 + (y-7)^2 = 49 and (x+5) + (y-7) = 7 are equivalent. However, Mark says that they aren't equal. Who is right? Explain.

Answer 1

I believe that Mark is correct because if you were to square each value in the equation, you would have: (x+25) + (y - 49) = 49, not (x+5) + (y-7) = 7.

Answer 2

Show Thomas a simplified example of why his idea is wrong

3^2 + 4^2 = 5^2 ---- true
then
3 + 4 = 5 ?????

If you want to take the square root, you have to take it of the whole side, not the individual terms

Answer 3

So, Mark would be correct. Those don't equal each other.