math
posted by Abby .
Please help me find the rule input 0 output 2 then input 1 output 4 next input 2 output 6 then input 3 output 8 last input 4 output 10
Thanks

If you suspect that the rule is a straight line,
y=mx+b
then find the slope using
m=(y2y1)/(x2x1)
Substitute m and (x1,y1) into the equation to find b.
Verify that the rule applies to all the points. 
First make a table to show input and output.
IN. OUT
0. 2
1. 4
2. 6
.. ..
Notice that the difference between outputs is 2.
But 2 times each input does NOT give the correct output. However, if you add 2 to the product of 2 and input, you get the correct output.
Therefore, the rule is 2x +2 where x is the input.