Răspuns:
ex 1.
[tex] \sqrt{0.5} = \sqrt{ \frac{5}{10} } = \sqrt{ \frac{1}{2} } = \frac{ \sqrt{1} }{ \sqrt{2} } = \frac{1}{ \sqrt{2} } [/tex]
raspuns corect: D
ex 2
[tex] - \frac{1}{7} = - \frac{7}{1} = - 7[/tex]
raspuns corect: B
ex 3
[tex]0.(6) - 1 = \frac{6}{9} - 1 = \frac{2}{3} - 1 = \frac{2 - 1 \times 3}{3} = - \frac{1}{3} [/tex]
raspuns corect: D
ex 7
linia mijlocie = (AD +CD ):2 =(9+13):2=22:2 = 11 cm
raspuns corect: B
ex. 5
[tex] \sqrt{5} \times + 3 = 8 \\ \sqrt{5} \times = 5 \\ x = \frac{5}{ \sqrt{5} } \\ x = \frac{5 \sqrt{5} }{5} \\ x = \sqrt{5} [/tex]
raspuns corect: A
ex. 6
[tex] \frac{2}{ \sqrt{6} } = \frac{2 \sqrt{6} }{ \sqrt{6 \times \sqrt{6} } } = \frac{2 \sqrt{6} }{6} = \frac{ \sqrt{6} }{3} [/tex]
raspuns corect: C
ex. 9
AB^2 +AC^2 = BC^2 (T. lui Pitagora)
3^2 + AC^2 =5^2
9+AC^2=25
AC^2=16
AC=4
Aria=(AB×AC):2=(3×4):2=12:2=6 cm^2
raspuns corect: D
