7 replies to this topic

[davidmarsh01]

Hello, this is my first post so go easy on me . Could anyone help me with this functions question? The function f(x)=a/x +b is such that f(-1)=3/2 and f(2)=9. Find the values of a and b. Thanks for any help

[Marcus]

good al fashioned simultaneous equations
first substitute in the two points given to get two equations

-1=a/(3/2) + b
-1=2a/3 + b

and

2=a/9+b

and solve using simultaneous equations

answers should be , I think XD
a=-5.4, b =2.6

any other questions just post again

[davidmarsh01]

good al fashioned simultaneous equations
first substitute in the two points given to get two equations

-1=a/(3/2) + b
-1=2a/3 + b

and

2=a/9+b

and solve using simultaneous equations

answers should be , I think XD
a=-5.4, b =2.6

any other questions just post again

I thought that if f(-1) = 3/2 then -1 would have to go in for the x term and 3/2 would go in for the f(x)? You seemed to do it the other way round?

[Marcus]

lol yeah you're right XD....I was em....testing you that's it
sorry XD

[davidmarsh01]

good al fashioned simultaneous equations
first substitute in the two points given to get two equations

-1=a/(3/2) + b
-1=2a/3 + b

and

2=a/9+b

and solve using simultaneous equations

answers should be , I think XD
a=-5.4, b =2.6

any other questions just post again

and f(x)=3/2 it is the whole function that is equal to 3/2 not just the x as you subbed in

[davidmarsh01]

lol yeah you're right XD....I was em....testing you that's it
sorry XD

so what is the answer?

[davidmarsh01]

lol yeah you're right XD....I was em....testing you that's it
sorry XD

so what is the answer?

i have it! b=6.5 and a=5

[Sep]

i was having problems with this myself, this topic baffles me