Sandra saves 12% of her salary for retirement this year jer salary was 3,000 more than in the previous year, and she saved $4,200. Wjat was her salary in the

.Um I don't feel like explaining but I can give you what I THINK the equation is:

 

"x" represents her last year's salary...

 

(.12) (3000 + x) = 4200

$4,200 / .12 =$35,000 her salary this year.

$35,000 - $3,000=$32,000 Her salary last year.

An equation representing this would look  something like this:

S=(C/I) - R, where, S=her salary last year, C=amount of her savings, I= rate of her savings, R=salary increase.