(4) In each of the following cases write down the normal vectors of the given lines and hence find the acute angles between them: (a) 2x - 5y - 3 = 0, 3r + 7y = 10; (b) 2r + 3y- 2 = 0, 2x 8y + 19 = 0, (c) 4y - 7y+ 13 = 0, 2x- 8y+ 19 0 (5) Use vector methods to find the position vectors of the points of intersection of the following pairs of lines: (a) r (i-i)+2= 0, r (3i+2j) + 6 = 0; (b) r (4i - j) - 3 = 0, r (i+2j) = 3; (c) 3x-y+4=0, 3x - 4y- 15 0, (d) 7x 4y +1 = 0, r- y +1 = 0.