$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.
The third one or last one, i’m thinking the third though
To solve this all you need to do is do the opposite of multipulcation:
1590/5
Which equal 318. To check you answer do 318×5
pi·18.6^2·123°/360° - 1/2·18.6^2·SIN(123°) = 226.3