Tìm x ∈ Z biết a)-x+8=-7 b)-148-2x=-260 c)12x+450=15x-162 d)-/x-5/=-7 e)(x-2).(5-x)=0 g)x^3=-64 h)(x-1)^5=-32 i)-(x+1)^2+81=0

Question

Tìm x ∈ Z biết
a)-x+8=-7
b)-148-2x=-260
c)12x+450=15x-162
d)-/x-5/=-7
e)(x-2).(5-x)=0
g)x^3=-64
h)(x-1)^5=-32
i)-(x+1)^2+81=0

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Madelyn 1 tháng 2021-10-28T14:31:37+00:00 2 Answers 3 views 0

Answers ( )

    0
    2021-10-28T14:32:43+00:00

    $a, -x+8=-7$
    $⇔-x=-7-8$
    $⇔-x=-15$
    $⇔x=15$

    $b, -148-2x=-260$
    $⇔-2x=-260+148$

    $⇔-2x=-112$
    $⇔x=56$

    $c, 12x+450=15x-162$

    $⇔12x-15x=-162-450$
    $⇔-3x=-612$
    $⇔x=204$
    $d, \left \{ {{-(x-5)=-7} \atop {-(5-x)=-7}} \right.$

    $⇔\left \{ {{-x+5=-7} \atop {-5+x=-7}} \right.$

    $⇔\left \{ {{-x=-12} \atop {x=-7+5}} \right.$

    $⇔\left \{ {{x=12} \atop {x=-2}} \right.$
    $e, (x-2)(5-x)=0$

    $⇔\left \{ {{x-2=0} \atop {5-x=0}} \right.$

    $⇔\left \{ {{x=2} \atop {x=5}} \right.$

    $g, x³=-64$

    $⇔x³=-4³$
    $⇔x=-4$

    $h, (x-1)^5=-32$
    $⇔(x-1)^5=-2^5$

    $⇔x-1=-2$
    $⇔x=-2+1$
    $⇔x=-1$

    $i, -(x+1)²+81=0$
    $⇔-(x+1)²=-81$
    $⇔\left \{ {{x+1=9} \atop {x+1=-9}} \right.$

    $⇔\left \{ {{x=8} \atop {x=-10}} \right.$ 

     

    0
    2021-10-28T14:32:58+00:00

    a) -x+8=-7

    -x=-7-8

    -x=-15

    x=15

    Vậy x=15

    b)-148-2x=-260

    -2x=-260+148

    -2x=-112

    x=-112/(-2)

    x=56

    Vậy….

    c)12x+450=15x-16

    12x-15x=-16-450

    -3x=-466

    x=-466/(-3)

    x=466/3

    Vậy…

    d) -/x-5/=-7

    =>x-5=7

    =>x=7+5

    =>x=12

    Vậy…

    e)(x-2).(5-x)=0

    =>x-2=0 hoặc 5-x=0

    x=0+2                x=5-0

    x=2                     x=5

    Vậy….

    g) x³=-64

    =>x=-4

    Vậy….

    h)(x-1)^5=-32

    =>x-1=2

    =>x=3

    Vậy….

    i)-(x+1)^2+81=0

    -(x+1)^2=-81

    =>x+1=9 hoặc x+1=-9

    x=8                     x=-10

    Vậy…

    Chúc bn hc tốt, cho mk 5 sao và ctlhn nha^^

     

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