Toán Lớp 7: Bài 1 1,x-45=48-68 2,35+5.(6-x)=(-12)+112 3,126=3.(x-9) 4,157-(x-124)=-483 5,46-(3x-2)mũ2=(-38)+20 6,13-|x+6|=-7-10 GIẢI GIÚP EM

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Toán Lớp 7:  Bài 1  1,x-45=48-68 2,35+5.(6-x)=(-12)+112 3,126=3.(x-9) 4,157-(x-124)=-483 5,46-(3x-2)mũ2=(-38)+20 6,13-|x+6|=-7-10       GIẢI GIÚP EM VỚI!!

lanminhngoc · Answer

1,   $x-45=48-68$ $&rArr;x-45=-20$ $&rArr;x=25$ Vậy $x=25$   2,   $35+5(6-x)=(-12)+112$ $&rArr;35+5(6-x)=100$ $&rArr;5(6-x)=65$ $&rArr;6-x=13$ $&rArr;x=-7$ Vậy $x=-7$ 3,   $126=3(x-9)$ $&rArr;x-9=42$ $&rArr;x=51$ Vậy $x=51$ 4,   $157-(x-124)=-483$ $&rArr;x-124=640$ $&rArr;x=764$   Vậy $x=764$   5,   $46-(3x-2)^2=(-38)+20$   $&rArr;46-(3x-2)^2=-18$ $&rArr;(3x-2)^2=64$ $+,3x-2=8$ $&rArr;3x=10$   $&rArr;x= dfrac{10}{3}$ $+,3x-2=-8$ $&rArr;3x=-6$ $&rArr;x=-2$ Vậy x&isin;{ frac{10}{3};-2}   6,   $13-|x+6|=-7-10$ $&rArr;13-|x+6|=-17$   $&rArr;|x+6|=30$   $+,x+6=30$ $&rArr;x=24$ $+,x+6=-30$ $&rArr;x=-36$ Vậy x&isin;{24;-36}

maingocquynhnhu2k1 · Answer

Lời giải và giải thích chi tiết:      1.   x - 45 = 48 - 68   x - 45 = -20   x = (- 25) +45   x = 25   2.   35+5.(6-x)=(-12)+|-112|   => 35+5.6-5x= -12+112   => 35+30-5x=100   =>5x=65-100   => 5x=-35   =>x=-35:5   => x=-7   3.   126=3.(x-9)   => x-9=42   => x=42+9   => 51   4.     157-(x-124)=-483    x-124= 157- (-483)   x-124= 640   x= 640+124   x= 764   5.    46 -  (3x-2)^2 = (-38)+20   => 46- (3x-2)^3 = -18   => (3x-2)^3 = 46 - (-18)   => (3x-2)^3 =64   => (3x-2)^3 = 4^3   => 3x-2=4   => 3x=4+2   => 3x=6   => x= 6:3   => 2   6.   TH1   13-|x+6| =-7-10   => $13-|x+6|=-17$    => |x+6| = 30      TH2     |x+6| = -30      => x=(-30)-6     => x=6