Question

sarahs investment grew 12% to $280 how much did she invest?

Answer 1

let x = the original amount
x + .12x = 280
1.12x = 280
x = 250

the original amount she invested is $250. :)

Answer 2

you could also do a check:
250 + .12(250) = 280?
250 + 30 = 280
280 = 280

so it checks out x3

Answer 3

i hope that makes sense