y-7 = x +a umm well first you have to get it into y=mx + b form by adding 7 to both sides
y= x + a +7 then you have to make a table of x and y for x, your table should generally go -2,-1,0,1 where u plug in these x values from -2 to 1 for x to solve for y then after you get the y u graph the coordinates.
for example you plug in -2, y = -2 + a + 7, y= a + 5 then you would graph the points
(-2, a+5) do this until you have enough points to make a rough sketch of the graph.