di bantu kak...butuh jawabannya Sekarang kak

[tex]nomor \: 3 \\ a = 2i + 3j - k \\ b = 4i - 2j + 6k \\ a) \: vektor \: c = 2a + b \\ = 2(2i + 3j - k) + 4i - 2j + 6k \\ = 4i + 6j - 2k + 4i - 2j + 6k \\ = (4 + 4)i + (6 - 2)j - (2 + 6)k \\ = 8i + 4j + 4k \\ b)panjang \: vektor \\ |a| = \sqrt{ {2}^{2} + {3}^{2} + ( { - 1}^{2}) } = \sqrt{4 + 9 + 1} = \sqrt{14} \\ |b| = \sqrt{ {4}^{2} + {( - 2)}^{2} + {6}^{2} } = \sqrt{16 + 4 + 36} = \sqrt{56} = 2 \sqrt{14} \\ |c| = \sqrt{ {8}^{2} + {4}^{2} + {4}^{2} } = \sqrt{64 + 16 + 16} = \sqrt{96} = 4 \sqrt{6} [/tex]