x的四次方+3x的平方-10=0
(x²+5)(x²-2)=0
(x²+5)(x+√2)(x-√2)=0
∴x=-√2 x=√2
2x的四次方+9x的平方-5=0
(2x²-1)(x²+5)=0
(√2x+1)(√2x-1)(x²+5)=0
∴x=-√2/2 x=√2/2