Решите уровнение и сделайте проверку

А) 5 (x-2) - 4x=-13

Б) 7 х-0,9 (10 х+20) = 4

В) 5+2 (8-3 х) - 21=2

1) 5 (x-2) - 4x=-13, 5x-10-4x=-13, x=-13+10, x=-3

L (-3) = 5 (-3-2) - 4. (-3) = 5. (-5) + 12=-25+12=-13

P (-3) = - 13, L (-3) = P (-3)

2) 7x-0,9 (10x+20) = 4, 7x-9x-18=4, - 2x=4+18, - 2x=22, x=-11

L (-11) = 7. (-11) - 0,9 (-110+20) = - 77-0,9. (-90) = - 77+81=4

P (-11) = 4, L (-11) = P (-11)

3) 5+2 (8-3x) - 21=2, 5+16-6x-21=2,21-6x-21=2,-6x=2, x=-1/3

L (-1/3) = 5+2 (8+1) - 21=5+2.9-21=5+18-21=23-21=2

P (-1/3) = 2, L (-1/3) = P (-1/3)

5 (х-2) - 4 х=-13

5 х-10-4 х=-13

5 х-4 х=-13+10

х=-3

5 (-3-2) - 4*-3=-13

7 х-0.9 (10 х+20) = 4

7 х-9 х-18=4

7 х-9 х=4+18

-2 х=22

х=22:-2

х=-11

7*-11-0.9 (10*-11+20) = 4

5+2 (8-3 х) - 21=2

5+16-6 х-21=2

-6 х=2-5-16+21

-6 х=2

х=2:-6

х=-0.333