c) 3000 -{123 ·4-[(x:3-271)-3·12] +125 ·12} egal 1243
{123 ·4-[(x:3-271)-3·12] +125 ·12} egal 1243+3000
{123 ·4-[(x:3-271)-3·12] +125 ·12} egal 4243
{123 ·4-[(x:3-271)-3·12] } egal 4243-125 ·12
{123 ·4-[(x:3-271)-3·12] } egal 2743
[(x:3-271)-3·12] egal 2743 +123 ·4
[(x:3-271)-3·12] egal 3235
(x:3-271) egal 3235+3·12
(x:3-271) egal 3271
x:3 egal 3271+271
x:3 egal 3542
x egal 3542 · 3
x egal 10626