Find the sum of the vectors `vec a = hat i -2 hat j + hat k`, `vec b = 2 hat i +4 hat j +5 hat k` and `vec c = 2 hat i -6 hat j -7 hat k`

Explanation

(a) The root of the equation f(x) = 0 occurs where graph y= f(x) meets the x-axis.
From the graph, roots of f(x) = 0 are x =- 1 and x = 2.
(b) The root of the equation f(x) = 4 occurs where the height of the graph is 4.
Hence the roots of f(x) = 0 are x = - 2 and x = 3.
(c) The root of the equation f(x) = 10 occurs where the height of the graph is 10.
Hence the roots of f(x) = 0 are x =- 3 and x =4.