Răspuns :
[tex]d) \\ \\ 3 \times ( - \sqrt{5}) = 3 \times - \sqrt{5} = - 3 \sqrt{5} [/tex]
[tex]e) \\ \\ ( - \frac{2}{5}) \times 2,5 = 2,5 = \frac{25}{10} ^{(5} = \frac{5}{2} = - \frac{2}{5} \times 2.5 = \frac{ - 2 \times 5}{5 \times 2} = - \frac{10}{10} = \frac{ - 1 \times 10}{1 \times 10} = - 1 [/tex]
[tex]f) \\ \\ 3 \frac{1}{4} \times ( - 1 \frac{3}{13}) = 1 \frac{3}{13} = \frac{1 \times 13 + 3}{13} = \frac{16}{13} = 3 \frac{1}{4} = \frac{3 \times 4 + 1}{4} = \frac{13}{4} = \frac{13}{4} \times ( - \frac{16}{13}) = \frac{13 \times ( - 16)}{4 \times 13} = - \frac{208}{52} = \frac{ - 4 \times 52}{1 \times 52} = - 4 [/tex]
[tex]g) \\ \\ - \frac{ \sqrt{3} }{4} \times \frac{ \sqrt{3} }{6} = - \frac{ \sqrt{3} \sqrt{3} }{4 \times 6} = - \frac{3}{24} ^{(3} = - \frac{1}{8} [/tex]
[tex]e) \\ \\ ( - \frac{2}{5}) \times 2,5 = 2,5 = \frac{25}{10} ^{(5} = \frac{5}{2} = - \frac{2}{5} \times 2.5 = \frac{ - 2 \times 5}{5 \times 2} = - \frac{10}{10} = \frac{ - 1 \times 10}{1 \times 10} = - 1 [/tex]
[tex]f) \\ \\ 3 \frac{1}{4} \times ( - 1 \frac{3}{13}) = 1 \frac{3}{13} = \frac{1 \times 13 + 3}{13} = \frac{16}{13} = 3 \frac{1}{4} = \frac{3 \times 4 + 1}{4} = \frac{13}{4} = \frac{13}{4} \times ( - \frac{16}{13}) = \frac{13 \times ( - 16)}{4 \times 13} = - \frac{208}{52} = \frac{ - 4 \times 52}{1 \times 52} = - 4 [/tex]
[tex]g) \\ \\ - \frac{ \sqrt{3} }{4} \times \frac{ \sqrt{3} }{6} = - \frac{ \sqrt{3} \sqrt{3} }{4 \times 6} = - \frac{3}{24} ^{(3} = - \frac{1}{8} [/tex]