a) x - 103 = -203

  x = 103 - 203

x = -100

b)x+ -36 = 0

x = 0 + 36

x=36

c)x - 105=150

x = 150 + 105

x = 255

d) x - (+21) = -29

x - 21 = -29

x = -29 + 21

x = -8

e) 5 + x = -7

x = -7-5

x=-12

f)-32-(x-5)=0

-32 - x + 5 = 0

x = -27

g) -12 + (x-9) = 0

x - 9 -12 = 0

x = 9+12

x=21

h)11 + (15-x) = 1

11 + 15 - x = 1

26 - x = 1

x = 26 - 1

x=25

= 2021 . ( -1990 - 72 ) - 2021 . ( 28 - 1990 )

 = 2021 . ( - 1990 - 72 - 28  + 1990 )

= 2021 . -100 = - 202100

\(\Leftrightarrow x+1=\sqrt{2x+10}\)

\(\Leftrightarrow x^2+2x+1=2x+10\)

\(\)\(\)\(\Leftrightarrow x^2-9=0\)

\(\Leftrightarrow\left(x-3\right)\left(x+3\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)