X^4-3x^2-28=0

Question

solving higher order polynomials by factoring. 

Answer 1

Hi Karin,

x⁴ -3x² -28=0

x⁴ -7x²+4x²-28=0

 

x²(x²-7) +4(x²-7)=0

(x²-7)(x²+4)=0

x² -7=0   or   x²+4=0

x² = 7     or x² =-4

x=±√7    or x= ±√-4 =± 2i

 

Check your answer by substituting the values of x in eq.