(2a+3b)(a^2-2ab+2b^2)=

( 2a + 3b ) ( a2 -2ab + 2b2 )
= 2a3 -4a2b + 4ab2 + 3a2b -6ab2 + 6b3
= 2a3 -a2b -2ab2 + 6b3

mohon koreksinya ^ ^