Question

16. Calculați: a) (√3-2)(√3+2)/¹00; c) (√8-√√2); b) (9-4√5) (9+4√5)"; d) (√3-√12)*.​

Answer 1

Răspuns:

$a) \: ( \sqrt{3} - 2) \div 100 = \frac{( \sqrt{3) ^{2} - 2 ^{2} } }{100} = \frac{ =3 - 2 ^{2} }{100} = \frac{3 - 4}{100} = \frac{ - 1}{100} = - \frac{1}{100}$

$b) \: (9 - 4 \sqrt{5} ) \times (9 + 4 \sqrt{5}) = {9}^{2} - (4 \sqrt{5} ) ^{2} = 81 - (4 \sqrt{5} ) ^{2} = 81 - {4}^{2} \times ( \sqrt{5} ) ^{2} = 81 - 16( \sqrt{5})^{2} = 81 - 16 \times 5 = 81 - 80 = 1$

$c) \: ( \sqrt{8} - \sqrt{2} ) = 2 \sqrt{2} - \sqrt{2} = \sqrt{2}$

$d )\: ( \sqrt{3} - \sqrt{12} ) = \sqrt{3} - 2 \sqrt{3} = - \sqrt{3}$