Find all values of x for which the curve f(x)=x^3-3x+4 is decreasing

Question

The answer is -1<x<1

Answer 1

y=x^3 -3x+4

dy/dx=slope=3x^2-3

y dekreez if slope <0

so set slope=0...3x^2=3

x^2=1

so x=1 or x=-1

look at the numbers & yu find slope < 0 wen abs(x) <1