Vectors A=7i^−4j^ and B (magnitude 10N, directed 30∘ below the positive x-axis) are given. A third vector C satisfies 2A+B+C=0. Calculate the magnitude and direction of C (direction to be given as the angle made with the positive x-axis, measured anticlockwise).
(a) 24N at 120∘
(b) 26N at 330∘
(c) 26N at 150∘
(d) 18N at 150∘