"

Answer Key 10.1

[latexpage]

  1. \(\begin{array}{rrrrr}
    \\ \\ \\ \\ \\ \\ \\ \\ \\ \\
    \sqrt{2x+3}&-&3&=&0 \\
    &+&3&&+3 \\
    \midrule
    (\sqrt{2x+3})^2&&&=&\phantom{+}(3)^2 \\ \\
    2x&+&3&=&9 \\
    &-&3&&-3 \\
    \midrule
    &&\dfrac{2x}{2}&=&\dfrac{6}{2} \\ \\
    &&x&=&3
    \end{array}\)
  2. \(\begin{array}{rrrrr}
    \\ \\ \\ \\ \\ \\ \\ \\ \\ \\
    \sqrt{5x+1}&-&4&=&0 \\
    &+&4&=&+4 \\
    \midrule
    (\sqrt{5x+1})^2&&&=&(4)^2 \\ \\
    5x&+&1&=&16 \\
    &-&1&&-1 \\
    \midrule
    &&\dfrac{5x}{5}&=&\dfrac{15}{5} \\ \\
    &&x&=&3
    \end{array}\)
  3. \(\begin{array}{rrrrrrrrr}
    \\ \\ \\ \\ \\ \\ \\ \\ \\ \\
    \sqrt{6x-5}&-&x&=&0&&&& \\
    &+&x&&+x&&&& \\
    \midrule
    (\sqrt{6x-5})^2&&&=&(x)^2&&&& \\ \\
    6x&-&5&=&x^2&&&& \\
    -6x&+&5&&&-&6x&+&5 \\
    \midrule
    &&0&=&x^2&-&6x&+&5 \\
    &&0&=&(x&-&5)(x&-&1) \\ \\
    &&x&=&5,&1&&&
    \end{array}\)
  4. \((\sqrt{7x+8})^2=(x)^2\)

    \(\begin{array}{rrrrrrrrr}
    7x&+&8&=&x^2&&&& \\
    -7x&-&8&&&-&7x&-&8 \\
    \midrule
    &&0&=&x^2&-&7x&-&8 \\
    &&0&=&(x&-&8)(x&+&1) \\ \\
    &&x&=&-1,&8&&&
    \end{array}\)

  5. \((\sqrt{3+x})^2=(\sqrt{6x+13})^2\)

    \(\begin{array}{rrrrrrr}
    3&+&x&=&6x&+&13 \\
    -3&-&6x&&-6x&-&3 \\
    \midrule
    &&\dfrac{-5x}{-5}&=&\dfrac{10}{-5}&& \\ \\
    &&x&=&-2&&
    \end{array}\)

  6. \((\sqrt{x-1})^2=(\sqrt{7-x})^2\)

    \(\begin{array}{rrrrrrr}
    x&-&1&=&7&-&x \\
    +x&+&1&&+1&+&x \\
    \midrule
    &&\dfrac{2x}{2}&=&\dfrac{8}{2}&& \\ \\
    &&x&=&4&&
    \end{array}\)

  7. \((\sqrt[3]{3-3x})^3=(\sqrt[3]{2x-5})^3\)

    \(\begin{array}{rrrrrrr}
    3&-&3x&=&2x&-&5 \\
    -3&-&2x&&-2x&-&3 \\
    \midrule
    &&\dfrac{-5x}{-5}&=&\dfrac{-8}{-5}&& \\ \\
    &&x&=&\dfrac{8}{5}&&
    \end{array}\)

  8. \((\sqrt[4]{3x-2})^4=(\sqrt[4]{x+4})^4\)

    \(\begin{array}{rrrrrrr}
    3x&-&2&=&x&+&4 \\
    -x&+&2&&-x&+&2 \\
    \midrule
    &&\dfrac{2x}{2}&=&\dfrac{6}{2}&& \\ \\
    &&x&=&3&&
    \end{array}\)

  9. \((\sqrt{x+7})^2\ge (2)^2\)

    \(\begin{array}{rrrrr}
    x&+&7&\ge &4 \\
    &-&7&&-7 \\
    \midrule
    &&x&\ge &-3
    \end{array}\)

  10. \((\sqrt{x-2})^2\le (4)^2\)

    \(\begin{array}{rrrrr}
    x&-&2&\le &16 \\
    &+&2&&+2 \\
    \midrule
    &&x&\le &18
    \end{array}\)

  11. \((3)^2 < (\sqrt{3x+6})^2 \le (6)^2\)

    \(\begin{array}{rrrcrrr}
    9&<&3x&+&6&\le &36 \\
    -6&&&-&6&&-6 \\
    \midrule
    \dfrac{3}{3}&<&&\dfrac{3x}{3}&&\le &\dfrac{30}{3} \\ \\
    1&<&&x&&\le &10
    \end{array}\)

  12. \((0)^2 < (\sqrt{x+5})^2 < (5)^2\)

    \(\begin{array}{rrrcrrr}
    0&<&x&+&5&<&25 \\
    -5&&&-&5&&-5 \\
    \midrule
    -5&<&&x&&<&20
    \end{array}\)

License

Icon for the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

Intermediate Algebra Copyright © 2020 by Terrance Berg is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.