Help: I need an equation for the following problems:

Question

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

Answer 1

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.

Answer 2

Could you break this down, step by step - and the teacher requires and equation for both

Thanks

Answer 3

from the first set of data, select two ordered pairs,
e.g. (3,8) and (5,14)
slope =(14-8)/(5-3)
= 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=3x-1
so when x=25
y=3(25)-1
= 74

do the second one the same way

Answer 4

Thanks so much - I do understand the logic - is there an easier way to set up this equation fro a 5th grader

Answer 5

2x-3(x+4)= -5

Answer 6

(1/3)y2+12=5x