Answer
$y=-5x+11$ or, in general form, $5x+y-11=0$
Work Step by Step
Through $(2,1)$ and $(1,6)$
Use the point-slope form of the equation of a line, which is $y-y_{1}=m(x-x_{1})$, where $(x_{1},y_{1})$ is a point through which the line passes and $m$ is the slope.
Two points through which the line passes are given. Use them to find the slope of the line.
$m=\dfrac{y_{2}-y_{1}}{x_{2}-x_{1}}=\dfrac{6-1}{1-2}=\dfrac{5}{-1}=-5$
Substitute $m$ and whichever of the given points into the formula and simplify to obtain the equation of this line:
$y-1=-5(x-2)$
$y-1=-5x+10$
$y=-5x+10+1$
$y=-5x+11$ or, in general form, $5x+y-11=0$