[tex]a)(2.1 + 2.9) { }^{2} = 2.1 {}^{2} + 2 \times 2.1 \times 2.9 + 2.9 {}^{2} = > {5}^{2} = ( \frac{21}{10}) {}^{2} + 12.18 + ( \frac{29}{10} ) {}^{2} = > 25 = \frac{441}{100} + \frac{609}{50} + \frac{841}{100} = > 25 = 25 \: da. \: adevarat[/tex]
[tex]b)(2.1 + 2.9) {}^{2} = 2.1 {}^{2} + 2.9 {}^{2} = > {5}^{2} = ( \frac{21}{10} ) {}^{2} + ( \frac{29}{10 } ) {}^{2} = > 25 = \frac{441}{100} + \frac{841}{100} = > 25 = \frac{641}{50} = > 25 = 12.82 \: nu \: fals[/tex]
