Question

Enumerati elementele multimilor:

Answer 1

D= { -16, -14,-12,-10,-8,-6,-4,-2,0,2}

-19<2x-1<19

-18<2x<20| :2

-9<x<10

-3| x

E={-6,-3, -1,1, 3,6,9}

13/ x+2

x+2€ D13

D13= { +_1 ; +_13}

x+2= -1

x= -3

x+2=1

x= -1

x+2=13

x=11

x+2=-13

x= -15

F={ -15, -3, -1, 11}

2x-3/x+5

x+5/x +5

x+5/ 2(x+5) -2x+3

x+5/ 2x+10 -2x+3

x+5/13

x+5€ D13

D13={+_1; +_13}

x+5=1

x= -4

x+5= -1

x= -6

x+5= 13

x=8

x+5= -13

x= -18

G={ -18, -6,-4,8}

x^2+x= 2(1+2+..+2021)

1+2+3+..+n= n(n+1)/2

1+2+3+..+2021= 2021 •2022/2= 2021• 1011= 2043231•2= 4086462

x(x+1)= 4086462

x=1

x+1= 4086462-1

x= 4086461

x=2

x+1 = 2043231

x= 2043230

x= 3

x+1= 1362154

x=6

x+1= 681077

x= 681076

H={ 1, 4086461 , 2, 2043230, 3, 6, 681076}