Question

Ex 6 pls imi trebuie urgent!!!! Dau coroana si multe puncte va rog!!!!!!​

Answer 1

Explicație pas cu pas:

x < 30 => 5n + 7 < 30

$5n < 23 \implies n < \frac{23}{5} = 4 \frac{3}{5} \\ \implies 0 \leqslant n \leqslant 4$

n = 0 => x = 7

n = 1 => x = 12

n = 2 => x = 17

n = 3 => x = 22

n = 4 => x = 27

=> C = {7; 12; 17; 22; 27}

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30 < y < 100 <=> 30 < n² < 100

$\sqrt{30} < n < \sqrt{100} \iff \sqrt{30} < n < 10 \\ 5 = \sqrt{25} < \sqrt{30} < \sqrt{36} = 6 \\ \implies 6 \leqslant n \leqslant 9$

n = 6 => y = 36

n = 7 => y = 49

n = 8 => y = 64

n = 9 => y = 81

=> D = {36; 49; 64; 81}