Find an equation of a line parallel to y=3x+2 and passes through the point (1,3). write answer form y=mx+b

If the line is parallel, it will have the same slope but a different y intercept.
So, so far y=3x+b.
Because we know that this parallel line goes through (1,3), we can substitute these co-ordinates to get b:
3=(3 x 1)+b
3=3+b
0=b
So the equation of the parallel line is as follows:
y=3x+0

Because they are parallel they have the same slope so m= 3
and then we can use the formula
(y-yo)=m (x-xo)
where 1 is xo and 3 is yo
after substitution
y-3=3x-3

y=3x+0