Example Question 3

Example corresponding to question 3 in algebra_2.

Example 1


If $P(x)=4x-3$ and $Q(x)=−x-1$ , then $P(x)−3 x Q(x)=$

  1. $-2x$
  2. $3x^2+7x+3$
  3. $x-3$
  4. $3x^2+x-3$
  5. $3x^2+7x-3$

Solution


  1. Substitute $P(x)$ by $4x-3$ and $Q(x)$ by $−x-1$ in the expression $P(x)−3 x Q(x)$ as follows

    $P(x)−3 x Q(x)=4x-3-3 x (-x-1)$


  2. Expand and group like terms

    $P(x)−3 x Q(x)=4x-3+3 x^2 + 3 x=3x^2+7x-3$

    Answer E