f.4 math呀

4x^4 - 17x^2+4=0
(4x^2-1)(x^2-4)=0
x^2=1/4 or x^2=4
x=1/2 or -1/2 or 2 or -2 (有答案要reject(剔除),請自己試)

9^[x(x+1)] = 27^(x+1)
3^2[x(x+1)] = 3^3(x+1)
2[x(x+1)] = 3(x+1)
2x^2+2x-3x-3=0
2x^2-x-3=0
(x+1)(2x-3)=0
x= -1 or x=3/2