Question

find out zeroes of f(x) =
${x}^{3} - 4x$

Answer 1

to find the zeroes, first equate the equation to 0
that is...
f(x)=0
x^3-4x=0
x(x^2-4)=0
x(x+2)(x-2)=0 {a^2-b^2=(a+b)(a-b)}
therefore...
x=0,
x+2=0 =>x= -2,
x-2=0 => x=2
therefore the zeroes of the equation are... 0, -2, 2..