Question

One factor of x4 + x2 – 20 is x? +5. The other factor is​

Answer 1

x⁴+x²-20=x⁴+5x²-4x²-20

=x²(x²+5)-4(x²+5)

=(x²-4)(x²+5)

clearly one factor is x²+5 and other factor is x²-4