Question

For the system shown below, what are the coordinates of the solution that lies in quadrant I? x^2-y^2=25
x+y=25

Answer 1

from second one, isolate x, what do you have?

Answer 2

y=-x+25

Answer 3

hihi, I suggest isolate x, you isolate y, but it's ok, now square both sides, show me what you have

Answer 4

oh my bad its x=-y+2 and squaring both sides gives me x^2=Y^2+20

Answer 5

no!!! the left hand side is x^2 but the right hand side is (-y+25)^2 or (25-y)^2 , open this perfect square, it is not y^2 +20, redo, please

Answer 6

x^2=y^2-50y+100

Answer 7

yup, now, take that x^2 replace to the first equation, what do you have?