Verified answer

[tex]a)x + 20 = 15 \\ x = 15 - 20 \\ x = - 5[/tex]

[tex]b) - 24 - x = - 20 \\ - x = - 20 + 24 \\ - x = 4 \\ x = - 4[/tex]

Ответ:

x+20=15

x=20-15

x=-5

-5+20=15

-24-x=-20

x=-20+24

x=4

-24-(-4)=20