please help me solve question 1, 2 and 3

1. Two vectors, a and b, have a common starting point with an angle of 120 between them. The vectors are such that a=3 and b=4. [A5] a) Calculate a+b. b) Calculate the angle between a and a+b. 2. If a=(1,3,3),b=(3,6,12) and c=(0,8,1), determine a+31bc. [K2] 3. Given the points A(2,1,3) and B(4,1,3), determine the coordinates of the point on the x-axis that is equidistant from these two points. [T5]