Question

решите уравнение 4x в  4 степени-13x²+9=0

Answer 1

Заменим x2 = t.
4t2 - 13t + 9 = 0.
D = 169 - 4*4*9 = 25.
t = 13 +- 5 / 2*4: t1 = 1, t2 = 9/4.
x2 = 1, x1 = -1, x2 = 1, x2 = 9/4, x3 = -3/2, x4 = 3/2.

Answer 2

$4 x ^{4} -13 x^{2} +9=0 \ x^{2} =t \ t^{2} -13t+9=0 \ D=169-9*4*4=169-144=25 \ sqrt{D} =5 \ t_{1} =1 \ t_{2} = frac{9}{4} \ x_{1} =+-1 \ x_{2} =+- frac{3}{2}$