Question

Iso e biquadrada,como e qui fas
4x4-17x²+4=0

Answer 1

$4x^4-17x^2+4=0 \\ \\ Substitui: \ y=x^2 \\ \\ 4y^2-17y+4=0 \\ \\ \Delta=(-17)^2-4.4.4=289-64=225 \\ \\ y=\frac{17 \pm \sqrt{225}}{2.4}=\frac{17 \pm 15}{8} \\ \\ y_1=\frac{1}{4} \\ \\ y_2=4 \\ \\ x^2=\frac{1}{4}\rightarrow x=\pm \frac{1}{2} \\ \\ x^2=4 \rightarrow x= \pm 2 \\ \\ \boxed{S=\{-\frac{1}{2}, \frac{1}{2}, -2, 2 \} }$

Answer 2

Olá.
4x⁴- 17x²+4=0
x²= u
4u²-17u+4=0
a= 4 b=-17 c=4
Δ= b²-4ac
Δ= (-17)² -4·4·4
Δ= 289 - 64
Δ= 225

u= -b +/- √Δ
           2a

u= 17 +/-√225
           2·4
u= 17+/-15
         8

u'= 17+15 =  4
           8

u''= 17-15=  2 = 1
          8         8     4

S:[1/4 ,4]

u=x²

logo u= {1/4 ,4}
1/4= x²
x'= √1/4
x'= + 1/2 , -1/2

4=x²
x=√4
x= +2, -2

S:{ +1/2, -1/2,+2,-2}