Answer:
Step-by-step explanation:
14)
[tex]\frac{3}{\sqrt{7}}=\frac{3*\sqrt{7}}{\sqrt{7}*\sqrt{7}}\\\\=\frac{3\sqrt{7}}{7}[/tex]
15a)
[tex]\frac{5}{\sqrt{2}}=\frac{5*\sqrt{2}}{\sqrt{2}*\sqrt{2}}\\\\=\frac{5\sqrt{2}}{2}\\[/tex]
b)(x + y)² - (x - y)² = 4xy
(2 + √3)² - (2 -√3)² = 4* 2 * √3
= 8√3
