Question

a line with a slope of -2 passes thru the coordinate (2,-1) and also passes thru the (2.y)

a) determine the value for y
b) determine another point on the line

Answer 1

y=mx+c

where m is the slope. simples

Answer 2

change in y
---------
change in x
y--1
----
2-2
y+1=0(-2)
y+1=0
y=-1