Please solve Only questions 1 , 6, 8 and 13

Points P, Q are given. Find the vector PQ and determine its norm. 1. P(1, -2, 5), Q ( 4, 2, 3). 2. P ( 4, 2, 0) , Q ( 2 , 4, 0 ) . 3. P(-4, 0, 7), Q(0, 3, - 1). Set a = (1, -2, 3), b = (3,0, -1), c = (-4, 2, 1). Find: 4. 2b + 3c. 5.- -2a + b - c. 6. a + 3b - 2c. Simplify the linear combinations. 7. (6j - k) + (3i - j + 2k). 8. 2(1 - j) + 6(21 + j - 2k). 9. 2(j + k) - 3(i + j - 2k). Calculate the norm of the vector. 10. 61 + 2j - k. 11. 2i + j - 2k. 12. >(i + 4j) - (3i+ k). 13. (i - j) + 2(j - i) + (k - j)