Question

A line has a slope of -1 and contains the points (1, 2) and (2, y). The value of y is

Answer 1

since slope=\[\frac{ y _{2}-y_{1} }{ x _{2} -x _{1}}\]

Answer 2

Plug in your values, and set it equal to -1

Answer 3

solve for y

Answer 4

(1.2)->(2,1) since the slope is calculated by
(y-2)/(2-1)=-1 -> y-2=-1 -> y=1