what is y in -2y-4.2=1.8+3y

-2y - 4.2 = 1.8 + 3y

This one is pretty easy. First, multiply through by ten to get rid of the decimals:

-20y - 42 = 18 + 30y

Isolate your variables:

-42 = 18 + 50y

-60 = 50y

Divide both sides by 50.

$${\mathtt{\,-\,}}{\frac{{\mathtt{60}}}{{\mathtt{50}}}}$$ = y

Simplify (cancel out 10's)

$${\mathtt{\,-\,}}{\frac{{\mathtt{6}}}{{\mathtt{5}}}}$$ = y

Then write it in correct notation:

{y: y = $${\mathtt{\,-\,}}{\frac{{\mathtt{6}}}{{\mathtt{5}}}}$$}