Question

Determina numarul a care este in Q, in urmatoarele cazuri:​

Answer 1

Explicație pas cu pas:

a)

$|a| = \frac{2}{3}$

$a = - \frac{2}{3} \\ a = \frac{2}{3}$

b)

$|3a| = \frac{3}{5}$

$3a = - \frac{3}{5} \implies a = - \frac{1}{5} \\ 3a = \frac{3}{5} \implies a = \frac{1}{5}$

c)

$|7 - a| = \frac{1}{2}$

$7 - a = - \frac{1}{2} \iff - a = - \frac{1}{2} - 7 \\ - a = - \frac{15}{2} \implies a = \frac{15}{2}$

$7 - a = \frac{1}{2} \iff - a = \frac{1}{2} - 7 \\ - a = - \frac{13}{2} \implies a = \frac{13}{2}$

d)

$|a| = - \frac{3}{4} < 0 \implies a \in \O$

e)

$|a| = 3\frac{1}{4}$

$a = - 3\frac{1}{4} \implies a = - \frac{13}{4}$

$a = 3\frac{1}{4} \implies a = \frac{13}{4}$

f)

$a = \Big| \frac{1}{3} - \frac{1}{2} \Big| = \Big| \frac{2 - 3}{6} \Big| = \Big| - \frac{1}{6} \Big| \\ \implies a = \frac{1}{6}$