Gradient of the line;
m = \(\frac{change in x}{change in y}\)
m=\(\frac{1-2}{2--3}\)
m=\(\frac{-1}{5}\)
Equation of line;
y=mx+c
y=\(\frac{-1}{5} x+c\)
Replacing for x and y;
1=\(\frac{-1}{5} *2+c\)
1=\(\frac{-2}{5} +c\)
c=\(\frac{7}{5}\)
y=\(\frac{-1}{5} x+ \frac{7}{5}\)