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Solve the equation rac92x−33x+3 = 1. 9. Given that 3 imes 91+x = 27^-x, find x. 10. Simplify rac135n imes 9ⁿ-1 imes 27ⁿ+1.

Mathematics

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9. Given that 3×91+x=27−x3 \times 9^{1+x} = 27^{-x}, find xx.

  1. Express all terms with the same base, which is 3.

    31×(32)1+x=(33)−x3^1 \times (3^2)^{1+x} = (3^3)^{-x}
  2. Apply the exponent rule (am)n=amn(a^m)^n = a^{mn}.

    31×32(1+x)=33(−x)3^1 \times 3^{2(1+x)} = 3^{3(-x)} 31×32+2x=3−3x3^1 \times 3^{2+2x} = 3^{-3x}
  3. Apply the exponent rule am×an=am+na^m \times a^n = a^{m+n} on the left side.

    31+(2+2x)=3−3x3^{1 + (2+2x)} = 3^{-3x} 33+2x=3−3x3^{3+2x} = 3^{-3x}
  4. Equate the exponents since the bases are the same.

    3+2x=−3x3+2x = -3x
  5. Solve for xx.

    3=−3x−2x3 = -3x - 2x 3=−5x3 = -5x x=−35x = -\frac{3}{5}

    The value of xx is −35\boxed{-\frac{3}{5}}.

    10. Simplify 135n×9n−1×27n+1\frac{1}{3^{5n}} \times 9^{n-1} \times 27^{n+1}.

  6. Express all terms with the same base, which is 3.

    135n×(32)n−1×(33)n+1\frac{1}{3^{5n}} \times (3^2)^{n-1} \times (3^3)^{n+1}
  7. Apply the exponent rules 1am=a−m\frac{1}{a^m} = a^{-m} and (am)n=amn(a^m)^n = a^{mn}.

    3−5n×32(n−1)×33(n+1)3^{-5n} \times 3^{2(n-1)} \times 3^{3(n+1)} 3−5n×32n−2×33n+33^{-5n} \times 3^{2n-2} \times 3^{3n+3}
  8. Apply the exponent rule am×an×ap=am+n+pa^m \times a^n \times a^p = a^{m+n+p}.

    3−5n+(2n−2)+(3n+3)3^{-5n + (2n-2) + (3n+3)} 3−5n+2n−2+3n+33^{-5n + 2n - 2 + 3n + 3}
  9. Combine the exponents.

    3(−5n+2n+3n)+(−2+3)3^{(-5n+2n+3n) + (-2+3)} 30n+13^{0n + 1} 313^1

    The simplified expression is 3\boxed{3}.

    11. Solve the equation 92x−33x+3=1\frac{9^{2x-3}}{3^{x+3}} = 1.

  10. Express all terms with the same base, which is 3.

    (32)2x−33x+3=30\frac{(3^2)^{2x-3}}{3^{x+3}} = 3^0
  11. Apply the exponent rule (am)n=amn(a^m)^n = a^{mn}.

    32(2x−3)3x+3=30\frac{3^{2(2x-3)}}{3^{x+3}} = 3^0 34x−63x+3=30\frac{3^{4x-6}}{3^{x+3}} = 3^0
  12. Apply the exponent rule aman=am−n\frac{a^m}{a^n} = a^{m-n}.

    3(4x−6)−(x+3)=303^{(4x-6) - (x+3)} = 3^0 34x−6−x−3=303^{4x-6-x-3} = 3^0 33x−9=303^{3x-9} = 3^0
  13. Equate the exponents since the bases are the same.

    3x−9=03x-9 = 0
  14. Solve for xx.

    3x=93x = 9 x=93x = \frac{9}{3} x=3x = 3

    The value of xx is 3\boxed{3}.

    12. (a) Solve 181(x−2)=27(1−x)\frac{1}{81^{(x-2)}} = 27^{(1-x)}.

  15. Express all terms with the same base, which is 3.

    1(34)x−2=(33)1−x\frac{1}{(3^4)^{x-2}} = (3^3)^{1-x}
  16. Apply the exponent rules 1am=a−m\frac{1}{a^m} = a^{-m} and (am)n=amn(a^m)^n = a^{mn}.

    (34)−(x−2)=33(1−x)(3^4)^{-(x-2)} = 3^{3(1-x)} 3−4(x−2)=33−3x3^{-4(x-2)} = 3^{3-3x} 3−4x+8=33−3x3^{-4x+8} = 3^{3-3x}
  17. Equate the exponents since the bases are the same.

    −4x+8=3−3x-4x+8 = 3-3x
  18. Solve for xx.

    8−3=−3x+4x8-3 = -3x+4x 5=x5 = x

    The value of xx is 5\boxed{5}.

    13. Evaluate 2÷(64125)−2/32 \div \left(\frac{64}{125}\right)^{-2/3}.

  19. Simplify the term with the negative exponent using (a/b)−m=(b/a)m(a/b)^{-m} = (b/a)^m.

    2÷(12564)2/32 \div \left(\frac{125}{64}\right)^{2/3}
  20. Apply the fractional exponent.

    Recall that am/n=(an)ma^{m/n} = (\sqrt[n]{a})^m.

    2÷(125643)22 \div \left(\sqrt[3]{\frac{125}{64}}\right)^2
  21. Calculate the cube roots.

    Note that 125=53125 = 5^3 and 64=4364 = 4^3.

    2÷(1253643)22 \div \left(\frac{\sqrt[3]{125}}{\sqrt[3]{64}}\right)^2 2÷(54)22 \div \left(\frac{5}{4}\right)^2
  22. Square the fraction.

    2÷52422 \div \frac{5^2}{4^2} 2÷25162 \div \frac{25}{16}
  23. Perform the division by multiplying by the reciprocal.

    2×16252 \times \frac{16}{25} 3225\frac{32}{25}

    The evaluated expression is 3225\boxed{\frac{32}{25}}.

    14. (a) Evaluate and express your answer in standard form; 4.56×3.60.12\frac{4.56 \times 3.6}{0.12}.

  24. Multiply the numbers in the numerator.

    4.56×3.6=16.4164.56 \times 3.6 = 16.416
  25. Divide the result by the denominator.

    16.4160.12=136.8\frac{16.416}{0.12} = 136.8
  26. Express the answer in standard form (scientific notation).

    A number in standard form is written as a×10na \times 10^n, where 1≤∣a∣<101 \le |a| < 10.

    136.8=1.368×102136.8 = 1.368 \times 10^2

    The evaluated expression in standard form is 1.368×102\boxed{1.368 \times 10^2}.

    14. (b) Without using mathematical tables or calculator, evaluate (73.8)2−(26.2)2(73.8)^2 - (26.2)^2.

  27. Use the difference of squares formula

    a2−b2=(a−b)(a+b)a^2 - b^2 = (a-b)(a+b).
    Here, a=73.8a = 73.8 and b=26.2b = 26.2.

  28. Substitute the values into the formula.

    (73.8−26.2)(73.8+26.2)(73.8 - 26.2)(73.8 + 26.2)
  29. Perform the subtraction and addition.

    73.8−26.2=47.673.8 - 26.2 = 47.6 73.8+26.2=100.073.8 + 26.2 = 100.0
  30. Multiply the results.

    47.6×100=476047.6 \times 100 = 4760

    The evaluated expression is 4760\boxed{4760}.

    15. (a) Simplify 0.016×0.0840.48\frac{0.016 \times 0.084}{0.48}. Leaving your answer in standard form.

  31. Convert the decimals to fractions or powers of 10 to simplify calculations.

    0.016=161000=16×10−30.016 = \frac{16}{1000} = 16 \times 10^{-3} 0.084=841000=84×10−30.084 = \frac{84}{1000} = 84 \times 10^{-3} 0.48=48100=48×10−20.48 = \frac{48}{100} = 48 \times 10^{-2}
  32. Substitute these into the expression.

    (16×10−3)×(84×10−3)48×10−2\frac{(16 \times 10^{-3}) \times (84 \times 10^{-3})}{48 \times 10^{-2}}
  33. Multiply the numbers in the numerator and combine powers of 10.

    (16×84)×(10−3×10−3)48×10−2\frac{(16 \times 84) \times (10^{-3} \times 10^{-3})}{48 \times 10^{-2}} 1344×10−648×10−2\frac{1344 \times 10^{-6}}{48 \times 10^{-2}}
  34. Divide the numerical parts and the powers of 10.

    134448×10−610−2\frac{1344}{48} \times \frac{10^{-6}}{10^{-2}} 28×10−6−(−2)28 \times 10^{-6 - (-2)} 28×10−6+228 \times 10^{-6 + 2} 28×10−428 \times 10^{-4}
  35. Express the answer in standard form (a×10na \times 10^n where $1 \le |

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