Решите уравнение ... 128+2x^4=40x^2

128 + 2 х^4 - 40 х^2=0

х^2=а

128 + 2 а^2 - 40 а = 0 делим на 2

а^2 - 20 а + 64 = 0

а = 16, а=4

х^2 = 16; х = 4 и х = - - 4

х^2 = 4; х=2 и х = - - 2

2X^4 - 40X^2 + 128 = 0

2 * (X^4 - 20X^2 + 64) = 0

X^2 = A

A^2 - 20A + 64 = 0

D = 400 - 4*1*64 = 400 - 256 = 144

V D = 12

A1 = (20 + 12) : 2 = 16

A2 = 8 : 2 = 4

X^2 = A

X^2 = 16

X1 = 4

X2 = ( - 4)

X^2 = 4

X3 = 2

X4 = ( - 2)