diketahui a= 2i + 3j dan b=3i - 4j tentukan a.3a b.4b c.2a+3b d.2a-3b apa jawab nya

a. 3a = 3 (2i+3j) = 6i +9j
b. 4b = 4 (3i-4j) = 12i-16j
c.2a+3b = 2(2i+3j) + 3(3i-4j) = 4i+6j+9i-12j =13i-6j
d.2a-3b= 2(2i+3j) - 3(3i-4j) = 4i+6j-9i+12j = -5i+18j