# Thread: indices

1. ## indices

hi need some assistance in figuring this out can u help me? Here's the question:

Given that {equ y= ax^b - 6} and that y=10 when x=2 and that y=48 when x=3 find the values of a and b.

i believe a simultaneous equation will form in order for me to figure out the values of a and b but i dont know how to form it...

2. Hi helloworld101

y= ax^b - 6

For x = 2 , y = 10 :
10 = a2^b - 6
a2^b = 16 .....................(1)

For x = 3 , y = 48 :
48 = a3^b - 6
a3^b = 54 .....................(2)

Divide the two equations

3. i dont understand can u elaborate more plz?

4. Hi helloworld101

You can try to divide equation (1) by equation (2) then write here what you've tried

5. ok i am not getting through with this sum plz explain more. i tried what u said but i not getting anything. ur help would be immensely appriciated...

6. $\frac{a \cdot 2^b = 16}{a \cdot 3^b = 54}$

$\frac{2^b}{3^b} = \frac{16}{54}$

continue ...

7. ## solution to problem

so this is what i got is the working correct along with the steps