MathEquations
posted by Vp .
Help: I need an equation for the following problems:
When x=25, y=?
In the function table the values for x are:
x = 3,5,7,9 and y = 8,14,20.26
#2
When x=8, y=?
In the function table the values for x are:
x = 0,2,4,6 and y = 8,18,28,38

In the first case, each increase of 2 in x increases y by 6 (three times as much as the increase in x). To get from x=9 to x=25, x must increasae by 16, so y must increase by 48, from 26 to 74.
#2 can be done the same way, and is even easier. Increase x by 2 and y must increase by 10. You don't need the equation. 
Could you break this down, step by step  and the teacher requires and equation for both
Thanks 
from the first set of data, select two ordered pairs,
e.g. (3,8) and (5,14)
slope =(148)/(53)
= 3
so the equation is y = 3x + b
but (3,8) lies on this so
8=3(3)+b
b=1
and the equation is
y=3x1
so when x=25
y=3(25)1
= 74
do the second one the same way 
Thanks so much  I do understand the logic  is there an easier way to set up this equation fro a 5th grader

2x3(x+4)= 5

(1/3)y2+12=5x