4/7 + X = 1/3 B,2/5+/2/3-X/=3/5 C,X=2^3.25^2 /10^2.5^3 D,3^X+2-3^X=648

4/7 + X = 1/3 B,2/5+/2/3-X/=3/5 C,X=2^3.25^2 /10^2.5^3 D,3^X+2-3^X=648

1 bình luận về “4/7 + X = 1/3 B,2/5+/2/3-X/=3/5 C,X=2^3.25^2 /10^2.5^3 D,3^X+2-3^X=648”

  1. Giải đáp:
    a) $x=-\dfrac{5}{21}$
    b) $x=\dfrac{7}{15}$ hoặc $x=\dfrac{13}{15}$
    c) $x=\dfrac{2}{5}$
    d) $x=4$
     
    Lời giải và giải thích chi tiết:
    a) $\dfrac{4}{7}+x=\dfrac{1}{3}$
    $x=\dfrac{1}{3}-\dfrac{4}{7}$
    $x=-\dfrac{5}{21}$
    b) $\dfrac{2}{5}+\left| \dfrac{2}{3}-x \right|=\dfrac{3}{5}$
    $\left| \dfrac{2}{3}-x \right|=\dfrac{3}{5}-\dfrac{2}{5}$
    $\left| \dfrac{2}{3}-x \right|=\dfrac{1}{5}$
    $\dfrac{2}{3}-x=\dfrac{1}{5}$ hoặc $\dfrac{2}{3}-x=-\dfrac{1}{5}$
    $x=\dfrac{2}{3}-\dfrac{1}{5}$ hoặc $x=\dfrac{2}{3}+\dfrac{1}{5}$
    $x=\dfrac{7}{15}$ hoặc $x=\dfrac{13}{15}$
    c) $x=\dfrac{{{2}^{3}}{{.25}^{2}}}{{{10}^{2}}{{.5}^{3}}}$
    $x=\dfrac{{{2}^{3}}.{{\left( {{5}^{2}} \right)}^{2}}}{{{\left( 2.5 \right)}^{2}}{{.5}^{3}}}$
    $x=\dfrac{{{2}^{3}}{{.5}^{4}}}{{{2}^{2}}{{.5}^{5}}}$
    $x=\dfrac{2}{5}$
    d) ${{3}^{x+2}}-{{3}^{x}}=648$
    ${{3}^{x}}{{.3}^{2}}-{{3}^{x}}.1=648$
    ${{3}^{x}}\left( {{3}^{2}}-1 \right)=648$
    ${{3}^{x}}.8=648$
    ${{3}^{x}}=648:8$
    ${{3}^{x}}=81$
    ${{3}^{x}}={{3}^{4}}$
    $x=4$

    Trả lời

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