Question

Y is partly constant and partly varies as x and when x=5,y=8 and when x=6,y=4.Find the equation connecting y and x

Answer 1

y = mx + b
so,
5m+b = 8
6m+b = 4
so solve for m and b

Answer 2

looks like our classical
y = mx + b
using (5,8)
8 = 5m + b **
using (6,4)
4 = 6m + b ***

subtract *** from ** and find m
once you have m you can find b