Môn Toán Lớp 7: 1,(-2/3)7.x=(-2/3)10 2,(x3/2)2=4/25 có 2 ý thou ak giúp me nhak:3

Question

Môn Toán Lớp 7:  1,(-2/3)^7.x=(-2/3)^10 2,(x+3/2)^2=4/25 có 2 ý thou ak giúp me nhak:3

thienthanh · Answer

1, (-2/3)^7 * x =(-2/3)^10   => x = (-2/3)^10 : (-2/3)^7   => x = (-2/3)^(10-7)   => x = (-2/3)^3   => x = -8/27   Vậy x = -8/27   2, (x+3/2)^2 = 4/25   => [((x+3/2)^2=(2/5)^2),((x+3/2)^2=(-2/5)^2):}   => [(x+3/2=2/5),(x+3/2=-2/5):}   => [(x=2/5-3/2),(x=-2/5-3/2):}   => [(x=-11/10),(x=-19/10):}   Vậy x = -11/10,x=-19/10

lanhuongthu · Answer

1) (-2/3)^7 &middot; x = (-2/3)^10   &rArr; x = (-2/3)^10 : (-2/3)^7   &rArr; x = (-2/3)^3   &rArr; x = -8/27   vậy x = -8/27   2) (x + 3/2)^2 = 4/25   &rArr; x + 3/2 = 2/5 hoặc x + 3/2 = -2/5   TH1 : x + 3/2 = 2/5       &rArr; x = 2/5 - 3/2       &rArr; x = -11/10   TH2 : x + 3/2 = -2/5       &rArr; x = -2/5 - 3/2      &rArr; x = -19/10   vậy x in {-11/10 ; -19/10}

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