Ok so we know that y=1 so we can simply sub in the value of y into the equation :
y = -5x +3
1 = -5x +3
Move the -5x to the LHS ( Left-hand-side ) therefore it changes sign as well move 1 to the RHS ( Right-hand-side ) it also changes sign.
5x = 3 - 1
5x = 2
x = 2/5
x = 0.4
Hope this helps :).
Let's pick two points on the line, the
y-intercept, and the
x-intercept. These are the points at which x=0, and y=0.
When x=0:

So one point is
(0,6)When y=0:

So another point is
(10,0)
So mark the points
(0,6) and
(10,0) on a pair of axes, and draw a straight line between them, and past them to infinity. This is a graphing of the line y=-3/5 x + 6