Find all solu fion 2 1o Solution11 x4 x2 12 0 Let x2 y y2 y

Find all solu fion 2. 1o.

11) x^4 +x^2 -12 =0

Let x^2 =y

y^2 +y -12 =0

y^2 +4y -3y -12 =0

y(y+4) -3(y +4) =0

(y -3)(y +4)=0

y =3 ; x^2 = 3

x= sqrt3 , -sqrt3

y+4 =0 ; x^2 +4 =0 ---> x= +/- 2i

Solution : x= sqrt3 , -sqrt3 , 2i , - 2i

12) 2x^2/3 +3x^1/3 -2 =0

Let x^1/3 = y

2y^2 +3y -2 =0

2y^2 +4y -y -2 =0

2y( y + 2) -1(y +2) =0

(2y -1)(y+2) =0

y = 1/2 ----->x^1/3 = 1/2

x= 1/8

y = -2 -----> x^1/3 = -2

x= -8

Solution : x= 1/8 , - 8

14) (t/(1+1)^2 +4(t/(t+1)) -12 =0

Let x = t/(t+1)

x^2 +4x -12 =0

x^2 +6x -2x -12 =0

x(x+6) -2(x+6) =0

(x-2)(x+6) =0

x=-2 ---->t/(t+1) =-2

t = -2t -2--->t = -2/3

t/(t+1) = -6 ---> t = -6t -6

7t = -6 ----> t =-6/7

t =-2/3 , -6/7 (solution)