Algebra · real student question

Find the root of the equation x - x/5 = -4/5.

Question

Find the root of the equation

xx5=45.x-\frac{x}{5}=-\frac{4}{5}.

Step-by-step solution

  1. Notice that both left-hand terms are multiples of the same unknown. There is nothing to expand and no brackets to clear — this is a one-step equation once xx and x/5x/5 are merged. Write the first term with the same denominator:

    x=5x5.x=\frac{5x}{5}.

  2. Combine the like terms.

    5x5x5=5xx5=4x5,\frac{5x}{5}-\frac{x}{5}=\frac{5x-x}{5}=\frac{4x}{5},

    so the equation collapses to

    4x5=45.\frac{4x}{5}=-\frac{4}{5}.

  3. Clear the common denominator. Multiply both sides by 55. Since the same factor of 55 sits under both sides, it disappears cleanly:

    4x=4.4x=-4.

  4. Divide by the coefficient of x.

    x=44=1.x=\frac{-4}{4}=-1.

  5. Substitute back into the original equation. With x=1x=-1 the left side is

    115=1+15=55+15=45,-1-\frac{-1}{5}=-1+\frac{1}{5}=-\frac{5}{5}+\frac{1}{5}=-\frac{4}{5},

    which equals the right side, so x=1x=-1 is the root.

Answer

x=1x=-1

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