Algebra · real student question

Solve 0.0272727x - 3.49091 = 0 for x.

Question

Solve for xx:

0.0272727x3.49091=00.0272727x-3.49091=0

Step-by-step solution

  1. Move the constant to the right. A single-step isolation:

    0.0272727x=3.490910.0272727x=3.49091

  2. Divide by the coefficient.

    x=3.490910.0272727=128.00016x=\frac{3.49091}{0.0272727}=128.00016\ldots

    That is suspiciously close to a whole number, which is worth investigating rather than reporting as-is.

  3. Recognise the coefficients as rounded repeating decimals. 0.02727270.0272727\ldots is the decimal form of 3110\dfrac{3}{110}, and 3.49090903.4909090\ldots is 384110\dfrac{384}{110}. The problem statement simply truncated both at five or six places.

  4. Redo the division with the exact fractions. The common denominator cancels outright:

    x=384/1103/110=3843=128x=\frac{384/110}{3/110}=\frac{384}{3}=128

    So the residual 0.000160.00016 in step 2 is entirely an artefact of the rounded input, not a feature of the problem.

  5. State both answers. Taking the printed decimals literally gives x128.0002x\approx 128.0002; the intended exact answer is x=128x=128. Whenever a decimal-coefficient equation lands within a rounding error of an integer, checking for hidden fractions like this is the right reflex.

Answer

x=128(the literal decimals give x128.0002)x=128\quad\text{(the literal decimals give }x\approx 128.0002\text{)}

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