\(a,\Leftrightarrow x+9=39\Leftrightarrow x=30\\ b,\Leftrightarrow73-x=69\Leftrightarrow x=4\\ c,\Leftrightarrow x+7=38\Leftrightarrow x=31\\ d,\Leftrightarrow x+4=178\Leftrightarrow x=174\\ e,\Leftrightarrow2\left(x-51\right)=16+20=36\Leftrightarrow x-51=18\Leftrightarrow x=69\\ f,\Leftrightarrow x-19=9\Leftrightarrow x=28\\ g,\Leftrightarrow4\left(x-3\right)=49-1=48\Leftrightarrow x-3=12\Leftrightarrow x=15\)
a) 45 - ( x + 9 ) = 6
45 - x = 6 + 9
45 - x = 15
x = 45 - 15
x = 30
b) 89 - ( 73 - x ) = 20
89 - x = 20 + 73
89 - x = 93
x = 93 - 89
x = 4
c) 198 - ( x + 4 ) = 120
198 - x = 120 + 4
198 - x = 124
x = 198 - 124
x = 74
d) ( x + 7 ) - 25 = 13
x - 25 = 13 + 7
x - 25 = 20
x = 20 + 25
x = 45
e) 2 ( x - 51 ) = 2.23 + 20
2 ( x - 51 ) = 64 + 20
2 ( x - 51 ) = 84
x - 51 = 84 - 2
x - 51 = 82
x = 82 + 51
x = 133
f) 450 : ( x - 19 ) = 50
450 : x = 50 - 19
450 : x = 41
x = 450 : 41
x = 24