Bài 1: Tính hợp lý 4) 4. (-2 ). (-13) . (-5) . 25 6) 25.135+(-25).35; 8) 115 – 3.[48 – 64 : (25 – 17)] Bài 2: 1) x – 9 = – 25

Question

Bài 1: Tính hợp lý
4) 4. (-2 ). (-13) . (-5) . 25
6) 25.135+(-25).35;
8) 115 – 3.[48 – 64 : (25 – 17)]
Bài 2:
1) x – 9 = – 25
3)15- ( 2 – 3x ) = 25
5) |x-5| = 5

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Charlie 2 tuần 2021-12-03T12:32:46+00:00 2 Answers 2 views 0

Answers ( )

    0
    2021-12-03T12:34:10+00:00

    Đáp án:

    Bài 1:

    4) 4 . (-2 ) . (-13) . (-5) . 25

    = 4 . (-5) . (-2) . 25 . (-13)

    = (-20) . (-50) . (-13)

    = 1000 . (-13)

    = -13000.

    6) 25 . 135 + (-25) . 35

    = 25 . 135 – 25 . 35

    = 25 . (135 – 35)

    = 25 . 100

    = 2500.

    8) 115 – 3 . [ 48 – 64 : (25 – 17) ]

    = 115 – 3 . [ 48 – 64 : 8 ]

    = 115 – 3 . [ 48 – 8 ]

    = 115 – 3 . 40

    = 115 – 120

    = -5.

    Bài 2:

    1) x – 9 = – 25

    x = -25 + 9

    x = -16

    3) 15 – ( 2 – 3x ) = 25

    2 – 3x = 15 – 25

    2 – 3x = -10

    -3x = -10 -2

    -3x = -12

    x = 4.

    5) |x – 5| = 5

    TH1: x – 5 = 5

    x = 5 + 5

    x = 10

    TH2: x – 5 = -5

    x = -5 + 5

    x = 0

    0
    2021-12-03T12:34:40+00:00

    Bài 1:

    4) $4. (-2 ). (-13) . (-5) . 25$

    $=(4.25).[(-2).(-5)].(-13)$

    $=100.10.(-13)$

    $=1000.(-13)$

    $=-13000$

    6) $25.135+(-25).35$

    $=25.(135-35)$

    $=25.100$
    $=2500$

    8)$115 – 3.[48 – 64 : (25 – 17)]$

    $=115 – 3.[48 – 64 : 8]$

    $=115 – 3.[48 – 8]$

    $=115-3.40$

    $=115-120$

    $=-5$

    Bài 2:

    1) $x – 9 = – 25$

    $⇒x=-25+9$

    $⇒x=-16$

    Vậy $x=-16$

    2) $15- ( 2 – 3x ) = 25$

    $⇒2-3x=15-25$

    $⇒2-3x=-10$

    $⇒3x=2-(-10)$
    $⇒3x=12$
    $⇒x=4$

    Vậy $x=4$

    5) $|x-5| = 5$

    $⇒$\(\left[ \begin{array}{l}x-5=5\\x-5=-5\end{array} \right.\) 

    $⇒$\(\left[ \begin{array}{l}x=5+5\\x=-5+5\end{array} \right.\) 

    $⇒$\(\left[ \begin{array}{l}x=10\\x=0\end{array} \right.\) 

    Vậy $x∈{\{10,0\}}$

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