# function rules

#### d

##### New member
write the function for each set of cards:Example of others Input/Output

rule being multiply by5 then subtract by 1 / rule being multiply by 2 then minus 10
1======4 1x5-1=4 5=======0 5x2-10
2======9 2x5-1=9 6=======2 6x2-10
3======14 3x5-1=14 7=======4 7x2-10
4======19 4x5-1=19 8=======6 8x2-10

NOW this one....
1========3
2========6
3========11
4========18

#### emmaiskool242

##### Junior Member
Ok I would like to help you but I'm a little lost on what you are trying to say, could you show me some of your work and/or try explaining your problem in a different way??

#### jolly

##### Junior Member
emmaiskool242 said:
Ok I would like to help you but I'm a little lost on what you are trying to say, could you show me some of your work and/or try explaining your problem in a different way??
That makes two of us. :wink:

jolly-no kidding

#### soroban

##### Elite Member
Hello, d!

I think I know what's going on . . .

Write the function for each set of cards:
Example of another

Code:
Input    Output     Rule: "times 5, minus 1"

1         4          1 x 5 - 1  =  4
2         9          2 x 5 - 1  =  9
3        14          3 x 5 - 1  = 14
4        19          4 x 5 - 1  = 19
The function is: $$\displaystyle \,f(x)\:=\:5x\,-\,1$$

Now determine the "rule" for this set:
Code:
Input     Output
1          3
2          6
3         11
4         18
The function seems to be: $$\displaystyle \.f(x)\:=\:x^2\,+\,2$$