Answer:
10y-30
Step-by-step explanation:
10*1y=10y
-3*10=-30
10y-30
If you mean 2x=40 x=20
but if you mean x^2=40 i think its x=80
'of' means multiply
half a dozen means 12/2=6
6 of one thing means 6 times x
plus means ad
half a dozen of another mean 6 times y
they are added
6x+6y
2 variables
it says 'of the other' so they are diferent