four *x^ three *(four *x^ four - five)*exp(-x^ four) = zero
4 multiply by x cubed multiply by (4 multiply by x to the power of 4 minus 5) multiply by exponent of ( minus x to the power of 4) equally 0
four multiply by x to the power of three multiply by (four multiply by x to the power of four minus five) multiply by exponent of ( minus x to the power of four) equally zero
4*x3*(4*x4 - 5)*exp(-x4) = 0
4*x3*4*x4 - 5*exp-x4 = 0
4*x³*(4*x⁴ - 5)*exp(-x⁴) = 0
4*x to the power of 3*(4*x to the power of 4 - 5)*exp(-x to the power of 4) = 0