Question

resolva : 9x4-13x²+4=0

Answer 1

 9x4-13x²+4=0
9(x²)²- 13x²+ 4 = 0

y = x²

9y² - 13y+ 4= 0

Δ = b² - 4ac
Δ= 13² - 4.9.4
Δ = 169 - 144= 25

$y= \frac{-b + \sqrt{delta} }{2a} = \frac{13+ \sqrt{25} }{2.9} = \frac{13+5}{18} = 1$

$y'= \frac{- (-13) - \sqrt{25} }{2.9} = \frac{13 - 5}{18} = \frac{4}{9}$