Question

разложите на множители: 1) 15xy-25y²;2)12a-4a;3)6a-6y+ab-by

Answer 1

$15xy-25y^2=5y(3x-5y) \ 12a-4a=4a(3-1) \ 6a-6y+ab-by=6(a-y)+b(a-y)=(a-y)(6+b)$