Quick Maths Question - Index Laws/Indices?

Question

If y = (x - 5)/2
then does y^2 = (x^2 - 25)/4
or is it y^2 = (x^2 + 25)/4

is the 25 positive or negative?

thanks in advance

Answer 1

you have a slight misunderstanding:

(x-5)^2 is not x^2-25, or x^2 + 25...it is:

(x-5)(x-5) = x^2-10x+25

so

y^2 = (x^2-10x+25)/4

Answer 2

y ² = (x - 5) ² / 4 is answer
If desired this could be shown as:-
y ² = (x ² - 10 x + 25) / 4