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

Toán Lớp 5: tìm x , biết a) x – 9178 = 121x 5 b) ( x + 1997) + 2003 = 5432 c) 125 – ( 25 + x ) = 7 x 9 d) 329 – ( 129 + x ) = 14 x 7 e) (x + 1) +

Toán Lớp 5: tìm x , biết
a) x – 9178 = 121x 5
b) ( x + 1997) + 2003 = 5432
c) 125 – ( 25 + x ) = 7 x 9
d) 329 – ( 129 + x ) = 14 x 7
e) (x + 1) + (x + 2) + (x + 3) + …….( x + 2020 ) = 2045250

Comments ( 2 )

  1. Giải đáp:
     
    Lời giải và giải thích chi tiết:
    $a) x – 9178 = 121 × 5$
    $⇒ x – 9178 = 605$
    $⇒ x = 605 + 9178$
    $⇒ x = 9783$
    $b) ( x + 1997) + 2003 = 5432$
    $⇒ x + 1997 = 5432 – 2003$
    $⇒ x + 1997 = 3429$
    $⇒ x = 3429 – 1997$
    $⇒ x = 1432$
    $c) 125 – ( 25 + x ) = 7 × 9$
    $⇒ 125 – ( 25 + x ) = 63$
    $⇒ 25 + x  = 125 – 63$
    $⇒ 25 + x  = 62$
    $⇒ x = 62 – 25$
    $⇒ x = 37$
    $d) 329 – ( 129 + x ) = 14 × 7$
    $⇒ 329 – ( 129 + x ) = 98$
    $⇒ 129 + x = 329 – 98 $
    $⇒ 129 + x =231$
    $⇒ x = 231 – 129$
    $⇒ x = 102$
    $ e) (x + 1) + (x + 2) + (x + 3) + …….+ ( x + 2020 ) = 2045250$
    $⇒ x + 1 + x + 2 + x + 3 + …… + x + 2020 = 2045250$
    $⇒ ( x + x + x + …. + x ) + ( 1 + 2 + 3 + ….. + 2020 ) = 2045250$
    $⇒ 2020 × x + 1010 × 2021 = 2045250$
    $⇒ 2020 × x + 2041210 = 2045250$
    $⇒ 2020 × x = 2045250 – 2041210$
    $⇒ 2020 × x = 4040$
    $⇒ x = 4040 : 2020 $
    $⇒ x = 2$

  2. a)
    x – 9178 = 121 × 5
    x – 9178 = 605
    x = 605 + 9178 = 9783
    b)
    (x + 1997) + 2003 = 5432
    x + 1997 = 5432 – 2003 = 3429
    x = 3429 – 1997 = 1432
    c)
    125 – (25 + x) = 7 × 9
    125 – 25 – x  = 63
    100 – x = 63
    x = 100 – 63 = 37
    d)
    329 – (129 + x) = 14 × 7
    329 – 129 – x = 98
    200 – x = 98
    x = 200 – 98 = 102
    e)
    (x + 1) + (x + 2) + …….. + (x + 2020) = 2045250
    (x + x + ………. + x) + (1 + 2 + ………… + 2020) = 2045250
    2020x + (2020 + 1) xx 2020 : 2 = 2045250
    2020x + 2041210 = 2045250
    2020x = 4040
    x = 2

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

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