Respuesta :

(x^2 - 9)(x^2 + 4)  the second sign gives the plus and minus signs in the factors.  The 9 and 4 have the difference of 5
JaniceneshiaSmith15
Answer:  x^4 + 5x^2 - 36 = 0 

Let u = x^2 and this becomes: 

(x^2)^2 + 5(x^2) - 36 = 0 
==> u^2 + 5u - 36 = 0 
==> (u + 9)(u - 4) = 0 

Sub back in x^2 

==> (x^2 + 9)(x^2 - 4) = 0 
==> (x^2 + 9)(x + 2)(x - 2) = 0 
==> x = ± 3i, x = -2, and x = 2 

Therefore, the solutions are 3i, -3i, 2 and -2. 

I hope that helps!