Final answer:
To form a perfect square trinomial, we need to add 3 more unit tiles to the expression x²+4x+3.
Step-by-step explanation:
To form a perfect square trinomial, we need to add a term that completes the square. In the expression x²+4x+3, the quadratic part is x²+4x. To complete the square, we need to add the square of half the coefficient of the x term, which is (4/2)² = 4. So, we need to add 4 to the expression to form a perfect square trinomial.
Therefore, 3 more unit tiles need to be added to the expression x²+4x+3 in order to form a perfect square trinomial.
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