Toán Lớp 8: Tìm x a)x mũ 2 -4=0 b)16x mũ 2 -1 =0 c)x mũ 3 -x=0 d) 4x mũ 2 ( x-2) tất cả mũ 2 =0

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Toán Lớp 8:  Tìm x  a)x mũ 2 -4=0 b)16x mũ 2 -1 =0 c)x mũ 3 -x=0 d) 4x mũ 2 ( x-2) tất cả mũ 2 =0

thucquyenlan · Answer

$@Shun$~   T&igrave;m x:   a) x^2 - 4 = 0   &hArr; x^2 - 2^2 = 0   &hArr; (x-2)(x+2) = 0   &hArr; $ left[ begin{matrix} x-2=0   x+2=0 end{matrix} right.$   &hArr; $ left[ begin{matrix} x=2   x=-2 end{matrix} right.$   Vậy x&isin;{2; -2}   b) 16x^2 - 1 = 0   &hArr; 16x^2 -1^2 = 0   &hArr; (16x - 1)(16x+1) = 0   &hArr; $ left[ begin{matrix} 16x-1=0   16x+1=0 end{matrix} right.$   &hArr; $ left[ begin{matrix} 16x=1   16x=-1 end{matrix} right.$   &hArr; $ left[ begin{matrix} x=  dfrac{1}{16}    x= dfrac{-1}{16}  end{matrix} right.$   Vậy x&isin;{ 1/16 ; - 1/16}   c) x^3 - x = 0   &hArr; x(x^2 - 1) = 0   &hArr; x(x -1)(x+1) = 0   &hArr; $ left[ begin{matrix} x=0    x-1= 0    x+1 = 0  end{matrix} right.$   &hArr;$ left[ begin{matrix} x=0    x=1    x= -1  end{matrix} right.$   Vậy x&isin;{0; 1; -1}   d) 4x^2 . (x-2)^2 = 0   &hArr; $ left[ begin{matrix} 4x^2 = 0    (x-2)^2= 0  end{matrix} right.$   &hArr; $ left[ begin{matrix} x^2=0    x-2=0  end{matrix} right.$   &hArr; $ left[ begin{matrix} x=0    x=2  end{matrix} right.$   Vậy x&isin;{0 ; 2}

kimnguenoanh · Answer

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