What is the value of x in the equation StartFraction 4 Over 7 EndFraction (StartFraction 21 Over 8 EndFraction x + one-half) = negative 2 (StartFraction 1 Over 7 EndFraction minus StartFraction 5 Over 28 EndFraction x)? Write your solution in decimal form.

1 answer

To solve the equation

\[ \frac{4}{7} \left(\frac{21}{8} x + \frac{1}{2}\right) = -2 \left(\frac{1}{7} - \frac{5}{28} x\right), \]

let's start by simplifying both sides step by step.

  1. Left Side:

    The left side is

    \[ \frac{4}{7} \left(\frac{21}{8} x + \frac{1}{2}\right). \]

    Distributing \(\frac{4}{7}\):

    \[ \frac{4}{7} \cdot \frac{21}{8} x + \frac{4}{7} \cdot \frac{1}{2}. \]

    Let's calculate each term separately:

    • For the \(x\) term: \[ \frac{4 \cdot 21}{7 \cdot 8} x = \frac{84}{56} x = \frac{3}{2} x. \]

    • For the constant term: \[ \frac{4 \cdot 1}{7 \cdot 2} = \frac{4}{14} = \frac{2}{7}. \]

    Thus, the left side simplifies to:

    \[ \frac{3}{2} x + \frac{2}{7}. \]

  2. Right Side:

    The right side is

    \[ -2 \left(\frac{1}{7} - \frac{5}{28} x\right). \]

    Distributing \(-2\):

    \[ -2 \cdot \frac{1}{7} + 2 \cdot \frac{5}{28} x. \]

    Calculating each term:

    • For the constant term: \[ -\frac{2}{7}. \]

    • For the \(x\) term: \[ \frac{10}{28} x = \frac{5}{14} x. \]

    Thus, the right side simplifies to:

    \[ -\frac{2}{7} + \frac{5}{14} x. \]

  3. Setting the two sides equal:

    Now we have the equation:

    \[ \frac{3}{2} x + \frac{2}{7} = -\frac{2}{7} + \frac{5}{14} x. \]

    First, eliminate the fractions by finding a common denominator, which is 14. Multiply each term by 14:

    \[ 14 \left(\frac{3}{2} x\right) + 14 \left(\frac{2}{7}\right) = 14 \left(-\frac{2}{7}\right) + 14 \left(\frac{5}{14} x\right). \]

    Simplifying each term results in:

    \[ 21x + 4 = -4 + 5x. \]

  4. Rearranging the equation:

    Now, let's move all \(x\) terms to one side and constants to the other:

    \[ 21x - 5x = -4 - 4, \] leading to

    \[ 16x = -8. \]

  5. Solving for \(x\):

    Now divide both sides by 16:

    \[ x = -\frac{8}{16} = -\frac{1}{2}. \]

  6. Writing in decimal form:

    Converting \(-\frac{1}{2}\) to decimal gives:

    \[ x = -0.5. \]

Thus, the final answer is

\[ \boxed{-0.5}. \]