ada yang tau cara nya ? Tolong d bantu ya caranya.......

i. -3ac+5bc+abc
= -3(-4)(-5)+5(2)(-5)+(-4)(2)(-5)
= -3(20)+5(-10)+40
= -60-50+40
=-110+40
=-70
ii. 2a+4bc-3ab
=2(-4)+4(2)(-5)+3(-4)(2)
=-8+4(-10)+3(-8)
=-8-40-24
=-72

iii. axbxc/b
=(-4)x(2)x(-5)/2
=(-4x) (2x) -5/2
=-8x²-5/2
iv. axc/2b
=(-4)x(-5)/2(2)
=(-4x) -5/4
=-4x-5/4