a)5(-8)x(-2)x(-3)
= -40x6
= -240
b)27x(15-12)-15(27-12)
= 27x15-27x12-15x27-15.12
= 27x(15-15)-27x12-15.12
= 27x0-12(27-15)
= 0-12.12
= 0-144
=-144
a) 5 * (-8)*(-2)*(-3)= [5*(-2)]*[(-8)*(-3)]= (-10)*24=-240
b)27*(15-12)-15*(27-12)=27*15-27*12-15*27+15*12
= (27*15-15*27)+15*12-27*12
=0+12*(15-27)
=12*(-12)
=-144