y=1-2x
y=x2-3x-5
i assume its y=(x^2)-3x-5 where x^2 means x squared.
Not sure what level you are at, but as both y's are the same, set them equal to one another, ie 1-2x=(x^2)-3x-5
then set them equal to zero ie 0=(x^2)-x-4
Then you can use the quadratic formula (if you know what that is) or you can factorise or complete the square.
Note- will not factorise properly so quad formula or completing square needed.
When using formula -> a=1, b=-1, c=-4
1(+or-) sqrt 1^2 - 4*1*-4, all divided by 2
1 plus root 17 all over 2 or 1 minus root 17 all over 2 :)