Question 500481
Let 
Daughter's monthly salary = x
Sylvia's monthly salary =2x-500
Given
Together they earn = $3,400
Daughter's monthly salary + Sylvia's monthly salary = 3400
x+(2x-500)=3400
x+2x-500=3400
3x-500=3400
3x=3400+500
3x=3900
Divide by 3 both sides of the equation
x=3900/3
x=1300
Daughter's monthly salary = $1300
Sylvia's monthly salary =2(1300)-500=2600-500=$2100