Algebra
posted by Mary on .
I need help finding a function rule.
X Y
4 3
2 0
0 3

So your function rule would be as follows:
(4,3), (2,0), (0,3)
Now use the formula to get the slope
m = (y2y1)/(x2x1)
(4,3) and (2,0)
m = (0(3))/(2(4))
m= 3/2
m=1.5
so this gives you
y = 1.5x +b
y= 1.5
x = 1
1.5 = 1.5 (1) = b
1.5 = 1.5 +b
b = 0
so your function is
f(x) 1.5x 
All I need is a function rule. For example, y= 1/2x + 1

Each increase in x by +2 causes y to increase by +3. Therefore the function is a straight line of the form
y = mx = b and the slope is m = 1.5. Yopu still need to determine the constant term, b.
Use any point such as (x=0, y=3) to get b.
3 = 1.5*0 + b
b = 3
y = 1.5 x + 3