Question

10. Calculaţi: a) |5-2√7|; b) |3√5-6|;​

Answer 1

$2 \sqrt{7} = \sqrt{ {2}^{2} \times 7} = \sqrt{28} \\ 5 = \sqrt{25} \\ = > \sqrt{25} < \sqrt{28} < = > 5 < 2 \sqrt{7} \\ = > |5 - 2 \sqrt{7} | < 0 \\ = > |5 - 2 \sqrt{7} | = |2 \sqrt{7} - 5| = 2 \sqrt{7} - 5$

$3 \sqrt{5} = \sqrt{ {3}^{2} \times 5} = \sqrt{45} \\ 6 = \sqrt{36} \\ |3 \sqrt{5} - 6| = 3 \sqrt{5} - 6$