Ka pliss bantuannya ka kurang paham makasih​

Jawaban:

a = 2i + 3j – 4k

b = 4i – 6j + 5k

c = 2i – 4j + 6k

2a – 3b + c = 2(2i + 3j – 4k) – 3(4i – 6j + 5k) + 2i – 4j + 6k

= 4i + 6j – 8k -12i + 18j -15k + 2i -4j +6k

= 4i -12i + 2i + 6j + 18j -4j -8k -15k + 6k

= -6i + 20j -17k ( D )