Răspuns:
Explicație pas cu pas:
1. {2a+5, b-15, 18} i. p. {2, 3, 5} =>
2*(2a+5)=3*(b-15)=5*18
2*(2a+5)=5*18=90 => 2a+5=45 => 2a=40 => a=20
3*(b-15)=5*18=90 => b-15=30 => b=45
2. {a, b, c} i. p. {[tex]\frac{1}{5}, \frac{3}{2}, \frac{4}{10}[/tex]} si 2a-3b+4c=216
a*[tex]\frac{1}{5}=[/tex]b*[tex]\frac{3}{2}[/tex]=c*[tex]\frac{4}{10}[/tex]
[tex]\frac{2a}{10}=\frac{15b}{10}=\frac{4c}{10}[/tex] |*10
2a=15b=4c
2a-3b+4c=216
15b-3b+15b=216
27b=216 => b=8 => 2a=15b=15*8=120 => a=60
=>4c=15b=15*8=120 => c=30
3. 9 muncitori ............25 ore
5 muncitori ...............x
5x=9*25=225 => x=45 ore
4. °[tex]\alpha +\beta[/tex]=180° => [tex]\alpha = 180°-\beta[/tex]
{[tex]\alpha , \beta[/tex]} i. p. {4, 6} => [tex]4\alpha =6\beta[/tex]
=> [tex]4*(180-\beta )=6\beta \\720-4\beta =6\beta \\720=10\beta \\\beta =72[/tex] => [tex]\alpha =180-\beta =180-72=108[/tex]
