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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 6: Bài 4: Thu gọn các biểu thức sau a) – ( a – b – c ) + ( b – c + d ) – ( – a + b + d ) b) ( a + b – c ) + ( a – b ) – ( a – b – c ) c)

Toán Lớp 6: Bài 4: Thu gọn các biểu thức sau
a) – ( a – b – c ) + ( b – c + d ) – ( – a + b + d )
b) ( a + b – c ) + ( a – b ) – ( a – b – c )
c) ( 71 + x ) – ( -24 – x ) + ( – 35 – x )
d) x – 34 – [ ( 15 + x ) – ( 23 – x ) ]
HỨA CHO 5* VÀ CTLHN Ạ!

Comments ( 1 )

  1. \text{a) Ta có: -(a-b-c)+(b-c+d)-(-a+b+d)}
    \text{=-a+b+c+b-c+d+a-b-d}
    \text{=(-a+a)+(b+b-b)+(c-c)+(d-d)}
    \text{=b}
    ___________________________________
    \text{b) Ta có: (a+b-c)+(a-b)-(a-b-c)}
    \text{=a+b-c+a-b-a+b+c}
    \text{=(a+a-a)+(b-b+b)+(-c+c)}
    \text{=a+b}
    ____________________________________
    \text{c) Ta có: (71+x)-(-24-x)+(-35-x)}
    \text{=71+x+24+x-35-x}
    \text{=(71+24-35)+(x+x-x)}
    \text{=60+x}
    ____________________________________
    \text{d) Ta có: x-34- [ ( 15 + x ) – ( 23 – x ) ]}
    \text{=x-34-(15+x-23+x)}
    \text{=x-34-(-8+2x)}
    \text{=x-34+8-2x}
    \text{=-x-26}
    ________________________________________
    $\text{-Áp dụng:Trước ngoặc là dấu trừ thì bên trong đổi dấu}$
    $\text{#mct}$

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222-9+11+12:2*14+14 = ? ( )