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Example 1
If $P(x)=4x-3$ and $Q(x)=−x-1$ , then $P(x)−3 x Q(x)=$
- $-2x$
- $3x^2+7x+3$
- $x-3$
- $3x^2+x-3$
- $3x^2+7x-3$
Solution
This example is about expanding and simplifying polynomials.
- Substitute $P(x)$ by $4x-3$ and $Q(x)$ by $−x-1$ in the expression $P(x)−3 x Q(x)$ as follows
$P(x)−3 x Q(x)=4x-3-3 x (-x-1)$
- Expand and group like terms
$P(x)−3 x Q(x)=4x-3+3 x^2 + 3 x=3x^2+7x-3$
Answer E
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