[tex]a)7 \sqrt{5} + 2 \sqrt{5} = (7 + 2) \sqrt{5} = 9 \sqrt{5} [/tex]
[tex]b)11 \sqrt{3} - 4 \sqrt{3} = (11 - 4) \sqrt{3} = 7 \sqrt{3} [/tex]
[tex]c)13 \sqrt{7} - 6 \sqrt{7} - 7 \sqrt{7} = (13 - 6 - 7) \sqrt{7} = 0 \sqrt{7} = 0 [/tex]
[tex]d) - 23 \sqrt{2} - 4 \sqrt{2} + 30 \sqrt{2} = ( - 23 - 4 + 30) \sqrt{2} = 3 \sqrt{2} [/tex]
[tex]e)5 \sqrt{37} + 2 - 5 \sqrt{37} + 10 = (5 \sqrt{37} - 5 \sqrt{37}) + (2 + 10) = 12 [/tex]
[tex]f)18 - 5 \sqrt{3} + 7 + 2 \sqrt{3} = (18 + 7) + ( - 5 \sqrt{3} + 2 \sqrt{3}) = 25 - 3 \sqrt{3} [/tex]
[tex]g)2 \sqrt{13} + 7 - (7 - 3 \sqrt{13}) = 2 \sqrt{13} + 7 - 7 + 3 \sqrt{13} = 2 \sqrt{13} + 3 \sqrt{13} = 5 \sqrt{13} [/tex]
[tex]h)3( \sqrt{5} - \sqrt{3}) + 5( \sqrt{3} + \sqrt{5}) = 3 \sqrt{5} - 3 \sqrt{3} + 5 \sqrt{3} + 5 \sqrt{5} = (3 \sqrt{5} + 5 \sqrt{5}) + ( - 3 \sqrt{3} + 5 \sqrt{3}) = 8 \sqrt{5} + 2 \sqrt{3} [/tex]
