Text Evaluate: (23+1)(23−1).(2\sqrt{3}+1)(2\sqrt{3}-1).(23+1)(23−1). Solution This is a difference of two squares: (23)2−12=4⋅3−1=12−1=11.(2\sqrt3)^{2}-1^{2}=4\cdot 3-1=12-1=11.(23)2−12=4⋅3−1=12−1=11. 11 \boxed{\,11\,}11