Question

how to find solutions for y=x² and y=-(x)² ?

Answer 1

To determine when these functions are equal to one another, set them equal to one another and solve for x,\[\Large\rm y=x^2, \qquad y=-x^2\]
\[\Large\rm x^2=-x^2\]Add x^2 to each side,\[\Large\rm 2x^2=0\]Divide by 2 then take square root,\[\Large\rm x=0\]