Bài 1:
a) ( – 468 + 7891 ) – ( – 68 + 891 + 41 )
b) – 6 . ( – 5 ) . ( – 18 ) . 15
c) – ( – 4 ) + 16 – [ ( – 84 ) – 35 ] + 61
Bài 2:
a) ( – 49 ) + ( – 6 ) – ( – 5 ) + x = – 2
b) ( – 3 ) . ( – 9 ) – x = ( – 6 ) – 11
Bài 1:
a) ( – 468 + 7891 ) – ( – 68 + 891 + 41 )
b) – 6 . ( – 5 ) . ( – 18 ) . 15
c) – ( – 4 ) + 16 – [ ( – 84 ) – 35 ] + 61
Bài 2:
a) ( – 49 ) + ( – 6 ) – ( – 5 ) + x = – 2
b) ( – 3 ) . ( – 9 ) – x = ( – 6 ) – 11
Câu hỏi mới
1)a)6559\\
b) – 8100\\
c)200\\
B2)a)x = 48\\
b)x = 44
\end{array}$
1)a)\\
\left( { – 468 + 7891} \right) – \left( { – 68 + 891 + 41} \right)\\
= – 468 + 7891 + 68 – 891 – 41\\
= \left( { – 468 + 68} \right) + \left( {7891 – 891} \right) – 41\\
= – 400 + 7000 – 41\\
= 6600 – 41\\
= 6559\\
b) – 6.\left( { – 5} \right).\left( { – 18} \right).15\\
= – \left( {6.15} \right).\left( {5.18} \right)\\
= – 90.90\\
= – 8100\\
c) – \left( { – 4} \right) + 16 – \left[ {\left( { – 84} \right) – 35} \right] + 61\\
= 4 + 16 + 84 + 35 + 61\\
= \left( {16 + 84} \right) + \left( {4 + 35 + 61} \right)\\
= 100 + 100\\
= 200\\
B2)\\
a)\left( { – 49} \right) + \left( { – 6} \right) – \left( { – 5} \right) + x = – 2\\
\Leftrightarrow – 49 – 6 + 5 + x = – 2\\
\Leftrightarrow – 50 + x = – 2\\
\Leftrightarrow x = – 2 + 50\\
\Leftrightarrow x = 48\\
Vậy\,x = 48\\
b)\left( { – 3} \right).\left( { – 9} \right) – x = \left( { – 6} \right) – 11\\
\Leftrightarrow 27 – x = – 6 – 11\\
\Leftrightarrow 27 – x = – 17\\
\Leftrightarrow x = 27 – \left( { – 17} \right)\\
\Leftrightarrow x = 27 + 17\\
\Leftrightarrow x = 44\\
Vậy\,x = 44
\end{array}$