Evaluate Expressions

Example corresponding about evaluating expressions

Example 1


If $x=2\dfrac{1}{4}$ and $y=2\dfrac{2}{3}$, then $4x-6y-6=$

  1. $-13$
  2. $13$
  3. $31$
  4. $-31$
  5. $22$

Solution

This example is about evaluating expressions.

  1. We first need to understand the mixed numbers. The mixed number $2\dfrac{1}{4}$ is equivalent to ${\color{red}{2+\dfrac{1}{4}}}$ and $2\dfrac{2}{3}$ is equivalent to ${\color{blue}{2+\dfrac{2}{3}}}$. We now substitute $x$ and $y$ by the mixed numbers ${\color{red}{2+\dfrac{1}{4}}}$ and ${\color{blue}{2+\dfrac{2}{3}}}$ in the given expression.

    $4x-6y-6$

    $=4{\color{red}{(2+\dfrac{1}{4})}}-6{\color{blue}{(2+\dfrac{2}{3})}}-6$


  2. We now now expand and simplify

    $= 4 \times 2 + 4 \times \dfrac{1}{4} -6 \times 2 - 6 \times \dfrac{2}{3}-6$

    $= 8 + 1 - 12 - 4 - 6$

    $= -13$

    Answer A
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