Express `-hat(i) - 3hat(j) + 4hat(k)` as linear combination of the vectors `2hat(i) + hat(j) - 4hat(k), 2hat(i) - hat(j) + 3hat(k)` and `3hat(i) + hat(j) - 2hat(k)`.

Answer

`bar(r) = 2 bar(a) + 2 bar(b) - 3 bar(c)`