$a) (x-35) - 120 = 0$
$x - 35 = 0 + 120$
$x - 35 = 120$
$x = 120 + 35$
$x = 155$
$b) 310 - (118 - x) = 217$
$118 - x = 310 - 217$
$118 - x = 93$
$x = 118 - 93$
$x = 25$
$c) 156 - (x + 61) = 82$
$x + 61 = 156 - 82$
$x + 61 = 74$
$x = 74 - 61$
$x = 13$
$d) 814 - (x - 305) = 712$
$x - 305 = 814 - 712$
$x - 305 = 102$
$x = 102 + 305$
$x = 407$
$e) ) 2x - 138 = 2 ³ . 3 ²$
$2x - 138 = 8 . 9$
$2x - 138 = 72$
$2x = 72 + 138$
$2x = 210$
$x = 210 : 2$
$x = 105$
$f) 20 - [7.(x - 3) + 4] = 2$
$7.(x - 3) + 4 = 20 - 2$
$7.(x - 3) + 4 = 18$
$7.(x - 3) = 18 - 4$
$7.(x - 3) = 14$
$x - 3 = 14 : 7$
$x - 3 = 2$
$x = 2 + 3$
$x = 5$
$g) [(6x - 39) : 3] . 28 = 5628$
$(6x - 39) : 3 = 5628 : 28$
$(6x - 39) : 3 = 201$
$6x - 39 = 201.3$
$6x - 39 = 603$
$6x = 603 + 39$
$6x = 642$
$x = 642 : 6$
$x = 107$
$h) 4x ³ + 12 = 120$
$4x ³ = 120 - 12$
$4x³ = 108$
$x³ = 108 : 4$
$x³ = 27$
⇒ $x³ = 3³$
⇒ $x = 3$
$i) 4. (x-1) + [( 4750 - 2160) - (1750 - 1160)] = 3000$
$4. (x-1) + [(4750 - 1750) - (2160 - 1160)] = 3000$
$4. (x-1) + [3000 - 1000] = 3000$
$4. (x-1) + 2000 = 3000$
$4. (x-1) = 3000 - 2000$
$4. (x-1) = 1000$
$x-1 = 1000 : 4$
$x-1 = 250$
$x = 250 + 1$
$x = 251$
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