Can you help me find the x-intercepts of

Question

of y=x^4-9? 

 

Answer 1

The equation y = x⁴ - 9

To find x - intercepts of equation substitute y = 0.

x⁴ - 9 = 0

Add 9 to each side.

x⁴ = 9

Apply square root on each side.

x² = ± 3

x² =  3 and x² = - 3

Again apply squre root on each side.

x = √(+3) and x = √(-3)

Case 1 : x = √(+3)

x = ± 1.732

Case 2 : x = √(-3)

Square root negative is not possible.It gives imaginary roots.

Imaginary roots does not cross the x axis.

Therefore, x intercepts are at x = ± 1.732.