Question

Y partly constant and partly varies directly as x=1,y=2 and when x=2,y=3 find the value of y when x=4

Answer 1

Y partly constant and partly varies directly as x ---> y = mx+b

and you are given
m+b = 2
2m+b = 3
so m=1 and b=1
y = x+1
so when x=4, y=5