Answer:
y = -x + 4
Step-by-step explanation:
to find the equation of a straight line with the slope and a pair of coordinates given the equation is
y - y1 = m(x - x1)
where x is the slope
x1 and y1 are the coordinates given
By substitution,
y - 3 = -1(x -1)
y - 3 = - x + 1
y = - x + 1 +3
y = -x + 4
