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If $x + y = 7$ and xy = 12,
the value of $(x^2 + y^2)$ is :

Answer: A. 25

-> $x^2 + y^2$ $$= (x + y)^2 - 2xy $$ $$=7^2 - 2(12)$$ $$= (49 - 24)= 25$$

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