Tìm x: a) x^4 - x^3 - 10x^2 + 2x + 4 = 0; b) (x + 3)^4 + ( x + 5) = 16

Tìm x
a) x^4 - x^3 - 10x^2 + 2x + 4 = 0
b) (x + 3)^4 + ( x + 5) = 16
c) 5x - 1/14 + 10x - 3/27 + 5x - 2/13 + 2x - 1/5 + 2(x - 5) = 0