Răspuns:
Explicație pas cu pas:
8.
[tex](2^5 + 2^2):6 + 2^2 + 2^1 + 2^0 - 1^{2015} =[/tex]
[tex]=(32 + 4):6 + 4 + 2 + 1 - 1 =[/tex].
[tex]=36:6 +6 =[/tex]
[tex]= 6 + 6 =[/tex]
[tex]= 12[/tex]
9.
[tex]a = [2,(6) + 1,2(3)]:0,026 + 0,19:0,01 =[/tex]
[tex]=( \frac{24}{9}+\frac{111}{90}): \frac{26}{1000} + \frac{19}{100} :\frac{1}{100} =[/tex]
[tex]=( \frac{8}{3}+\frac{37}{30}): \frac{13}{500} + \frac{19}{100}*100=[/tex]
[tex]=( \frac{80}{30}+\frac{37}{30}): \frac{13}{500} + \frac{19}{100}*100=[/tex]
[tex]=\frac{117}{30}*\frac{500}{13} + 19 =[/tex]
[tex]=\frac{3*3*13}{10*3}*\frac{50*10}{13} + 19 =[/tex]
[tex]=3*50+ 19 =[/tex]
[tex]= 150 + 19 =[/tex]
[tex]= 169 =[/tex]
[tex]= 13^2[/tex]
este patrat perfect.
10.
a)
17 dm = 1,7 m
200 cm = 2 m
volumul = 0,3 * 1,7 * 2 = 1,02 m cubi.
b)
1 m cub = 1000 litrii.
1,02*1000/0,5 = 2040 sticle
11
Notam cu x, y si z cele trei numere
avem:
(x + y + z)/3 = 14
si
x = y + 7
z = 3*y
(y + 7 + y + 3*y)/3 = 14
(5*y + 7)/3 = 14
5*y + 7 = 14*3
5*y + 7 = 42
5*y = 42 - 7
5*y = 35
y = 35/5
y = 7
Si atunci
x= y + 7 = 7 + 7 = 14
z = 3*y = 3*7 = 21
