What constant should be added to the expression x² + 3x to create a perfect square trinomial?

To transform the expression x² + 3x into a perfect square trinomial, we follow the steps outlined below:

  • A perfect square trinomial takes the general form of (a + b)², which expands to a² + 2ab + b².
  • In our expression, we have a = x (since it corresponds to ), and we need to determine the value of b to complete the square.
  • The coefficient of x in our expression is 3. According to the perfect square trinomial formula, 2ab = 3x implies that 2x * b = 3.
  • Solving for b, we rearrange to find b = rac{3}{2}.
  • Now we must add to complete the square. Calculating gives us:

b² = igg( rac{3}{2}igg)² = rac{9}{4}.

Thus, to turn x² + 3x into a perfect square trinomial, we need to add </strong> </strong> </strong> </strong> </strong> </strong> 9/4.

As a result, the complete expression becomes:

x² + 3x + rac{9}{4} = igg(x + rac{3}{2}igg)².

This confirms that the constant to be added is rac{9}{4}.

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