Find intercepts, linear function, f(2)=-2 and f(3)-f(9)=15

[chip]

I need to find the intercepts of the graph of f.

For a linear function f, f(2)= -2 and f(3) - f(9)= 15

I do not know where to start, I am used to having an equation in y=mx+b form or at least an equation that I can change into that form.
If I had a starting point I may be able to go on from there, but I don't know what to do with the information given, any tips would be great.

 

[Deleted member 4993]

I need to find the intercepts of the graph of f.

For a linear function f, f(2)= -2 and f(3) - f(9)= 15

I do not know where to start, I am used to having an equation in y=mx+b form or at least an equation that I can change into that form.
If I had a starting point I may be able to go on from there, but I don't know what to do with the information given, any tips would be great.

Can we assume f(x) is a linear function?

Please tell us the definitions of:

1) x - intercept of a graph (what would you expect the value of y to be at x_intercept?)

2) y - intercept of the graph (what would you expect the value of x to be at y_intercept?)

3) The slope of a function at a point

 

[chip]

Can we assume f(x) is a linear function?

Please tell us the definitions of:

1) x - intercept of a graph (what would you expect the value of y to be at x_intercept?)

2) y - intercept of the graph (what would you expect the value of x to be at y_intercept?)

3) The slope of a function at a point

1. X-intercept is a point in the equation where the y value is zero. Somewhere on the x axis. Example: (5,0)
2. Y-intercept is a point in the equation where the x value is zero. Somewhere on the y axis. Example: (0,5)

3. The slope of a function at any point is equal to the slope of its tangent line at that point.

f(x) at x=a [f(a+h)-f(a)] / h

How I put f(2)=-2 and f(3)-f(9)=15 into the formula = I have no clue, if that's what your supposed to do.

 

[daon2]

Rewrite your given as: f(9)-f(3)=-15. Lines have constant slope.

For the above, what is a? What is h? Can you put it in the form you have written above? When you do, what you have on the other side of the equal sign is you slope m.

Alternatively, write f(x)=mx+b. Then f(2)=-2 tells you that -2=2m+b, or that b=-2-2m. So you may write f(x) = mx-(2+2m).

Then you my find m very easily with f(3)-f(9)=15.

 

[burakaltr]

I need to find the intercepts of the graph of f.

For a linear function f, f(2)= -2 and f(3) - f(9)= 15

I do not know where to start, I am used to having an equation in y=mx+b form or at least an equation that I can change into that form.
If I had a starting point I may be able to go on from there, but I don't know what to do with the information given, any tips would be great.

y=ax+b

-2=2a+b
3a-9a=15

solve and find (0,b) and (-b/a,0)