1)t4-1/5t2+1/100=0 2)(2z2+11z)2-23(2z2+11z)+126=0 3)(x2-4x+1)(x2-4x+2)=12

2) пусть 2z^2 +11z = a

a^2 - 23a +126=0

a = 9   a = 14

2z^2 +11z = 9

2z^2 +11z-9 = 0

z = -4,5     z = 1

2z^2 +11z = 14

2z^2 +11z - 14 =0

z = -3.5     z   =-2

3) x^2 -4x = a

(a+1) (a+2) =12

a^2 +3a +2 = 12

a^2 +3a -10 = 0

a = 2     a= - 5

x^2 -4x = 2

x^2 -4x -2 =0

x^2 -4x = -5

x^2 -4x + = 0