Explicație pas cu pas:
a=3√5+√2, b=2√5-√2
[tex]a + b = 3 \sqrt{5} + \sqrt{2} + 2 \sqrt{5} - \sqrt{2} = 5 \sqrt{5} \\ [/tex]
[tex]a - b = 3 \sqrt{5} + \sqrt{2} - 2 \sqrt{5} + \sqrt{2} = \sqrt{5} + 2 \sqrt{2} \\ [/tex]
a= 4√3-2√6, b=7√6 +√3
[tex]a + b = 4 \sqrt{3} - 2 \sqrt{6} + 7 \sqrt{6} + \sqrt{3} = 5 \sqrt{3} + 5 \sqrt{6} = 5( \sqrt{3} + \sqrt{6}) \\ [/tex]
[tex]a - b = 4 \sqrt{3} - 2 \sqrt{6} - 7 \sqrt{6} - \sqrt{3} = 3 \sqrt{3} - 9\sqrt{6} = 3( \sqrt{3} - 3\sqrt{6}) \\ [/tex]
a=2√3+3√5+5√7, b=5√7-2√3
[tex]a + b = 2 \sqrt{3} + 3 \sqrt{5} + 5 \sqrt{7} + 5 \sqrt{7} - 2 \sqrt{3} = 3 \sqrt{5} + 10 \sqrt{7} \\ [/tex]
[tex]a - b = 2 \sqrt{3} + 3 \sqrt{5} + 5 \sqrt{7} - 5 \sqrt{7} + 2 \sqrt{3} = 4 \sqrt{3} + 3 \sqrt{5} \\ [/tex]
