Answer:
23x + 12y + -4xy^2
Step-by-step explanation:
So lets first expand
3y (-4 x(5x - 3y + y^2)
let's ignore 3y for now
Since 5x - 3y + y^2 can't be simplified, we move on to multiplying each number.
note: Capital X = Multiplying symbol
___________________________________
-4 X 5x, -4 X - 3y, -4 X y^2
= -20x + 12y + -4xy^2
now we bring back the 3x
3x - -20x + 12y + -4xy^2
so now we simplify, by finding like terms
= 23x + 12y + -4xy^2
