Explicație pas cu pas:
[tex]a)x = |4 \sqrt{5} - 9 | + |4 \sqrt{5} - 7| \\ \\ x = - (4 \sqrt{5} - 9) + (4 \sqrt{5} - 7) \\ \\ x = - 4 \sqrt{5} + 9 + 4 \sqrt{5} - 7 \\ \\ x = ( - 4 \sqrt{5} + 4 \sqrt{5}) + (9 - 7) \\ \\ x = 0 + 2 \\ \\ x = 2 [/tex]
[tex]b)x = |10 - 7 \sqrt{2} | + |9 - 7 \sqrt{2} | \\ \\ x = | - 7 \sqrt{2} + 10 | + | - 7 \sqrt{2} + 9 | \\ \\ x = ( - 7 \sqrt{2} + 10) - ( - 7 \sqrt{2} + 9) \\ \\ x = - 7 \sqrt{2} + 10 + 7 \sqrt{2} - 9 \\ \\ x = ( - 7 \sqrt{2} + 7 \sqrt{2}) + (10 - 9) \\ \\ x = 0 + 1 \\ \\ x = 1 [/tex]
[tex]c)x = |6 \sqrt{3} - 11 | - |13 - 6 \sqrt{3} | \\ \\ x = - (6 \sqrt{3} - 11) - | - 6 \sqrt{3} + 13 | \\ \\ x = - (6 \sqrt{3} - 11) - ( - 6 \sqrt{3} + 13) \\ \\ x = - 6 \sqrt{3} + 11 + 6 \sqrt{3} - 13 \\ \\ x = ( - 6 \sqrt{3} + 6 \sqrt{3}) + (11 - 13) \\ \\ x = 0 - 2 \\ \\ x = - 2 [/tex]
[tex]d)x = |5 \sqrt{7} - 13 | - |10 - 5 \sqrt{7} | \\ \\ x = (5 \sqrt{7} - 13) - | - 5 \sqrt{7} + 10 | \\ \\ x = (5 \sqrt{7} - 13) + ( - 5 \sqrt{7} + 10) \\ \\ x = 5 \sqrt{7} - 13 - 5 \sqrt{7} + 10 \\ \\ x = (5 \sqrt{7} - 5 \sqrt{7}) + ( - 13 + 10) \\ \\ x = 0 - 3 \\ \\ x = - 3 [/tex]
