Question

Solve for x : 7/8 = 21/x

Answer 1

Hey!

We could write the problem like this,

`(7)/(8)=(21)/(x)`
Cross multiply!

`7x=8\cdot \:21`
We know that
`8\cdot \:21=168`, let's plug that in.

`7x=168`
Divide both sides by 7.

`(7x)/(7)=(168)/(7)`

Our final answer would be,

`x=24`

Thanks!
-TetraFish

Answer 2

`(21)/(1) (7)/(8) = (21)/(x) ( (21)/(1) ) \\ Cross-out, the DOUBLE 21's \\ 7(x) = 21 \\ 21(8) = ? \\ 7(x) = 168 \\ (168)/(7) = 24 \\ Answer: x = 24`
`Choice. 2`