Question

Two quantities x and y are such that y is partly constant and partly varies as x . Given that x=3, y=7 and when x=8,y=22.Find the equation connecting x and y

Answer 1

y=3x-2

Explanation:

(3,7) &(8,22)

`(y_(2)-y_(1))/(x_(2)-x_(1))`=
`(22-7)/(8-3) = (15)/(5)=3`

y=3x+b

7=(3*3)+b

7=9+b

b=-2