Question

The line passing through point (2,4) parallel to the line whose equation is y=x

Answer 1

Line y=x has a slope of m=(1/1)=1
The line with slope m=1 passing through (x1,y1)=(2,4) has the equation

(y-y1)=x-x1
=>
y-4=x-2
=>
y=x+2