Solve each equation by finding all roots x^4-16=0
add both sides by 16so you'll have x^4 =16take the 4th root of both sides and you'll get x= 2
\({ x }^{ 4 }-16=0\\ \\ { x }^{ 4 }=16\\ \\ x=\pm \sqrt [ 4 ]{ 16 } \\ \\ \therefore \quad x=\pm 2\)