Question

Разложите на множители (a+3)^2-9(a-1)^2

Answer 1

(а+3)^2-9(а-1)^2=а^2+6а+9-9(а^2-2а+1)=а^2+6а+9-9а^2+18а-9=
=-8а^2+24а=8а×(3-а)

Answer 2

(  a + 3 )^2 - 9( a - 1 )^2 = ( a + 3 )^2 - ( 3( a - 1 ))^2 = ( a + 3 )^2 - ( 3a - 3 )^2 =
= ( a + 3 + 3a - 3 )( a + 3 - 3a + 3 ) = 4a*( 6 - 2a )