Hello!
First you multiply Y by each of the values in the second parenthesis
Y * Y = Y^2
Y * -5 = -5Y
Now you do the same thing again but with the 10
10 * Y = 10Y
10 * -5 = -50
Put the values together
Y^2 - 5Y + 10Y - 50
Combine like terms
Y^2 + 5Y - 50
The answer is Y^2 + 5Y - 50
Hope this helps!