[tex]y=2x \newline y= x^{2} -3[/tex]
Substitue 2x for y in the second equation:
[tex]2x= x^{2} -3[/tex]
Rearrange to [tex]a x^{2} +bx+c=0[/tex] form:
[tex] x^{2} -2x-3=0[/tex]
Factor:
[tex](x-3)(x+1)=0[/tex]
Zeros are [tex]x=3[/tex] and [tex]x=-1[/tex]
To find y-coordinates of pts of intersection, plug these x-values into first equation to get [tex]y=-2[/tex] and [tex]y=6[/tex]