How would I work out a problem like this?? (ratios and proportions)

Question

I'm a little rusty on ratios and proportions because I haven't done them in a while.
My problem is $(x-1)/8=(x+2)/10$

1708 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-07-10T07:57:58

$x=13$

By cross multiplication we get
$10(x-1)=8(x+2)$
dividing by $2$

$5(x-1)=4(x+2)$
expanding

$5x-5=4x+8$
adding $5$ and subtracting $4x$

$x=13$