Va rog mult sa ma ajutati

Răspuns:
a. x-12,5=(13×5+1)/5
x-12,5=66/5
x-12,5=13,2
x=13,2+12,5
x=25,7
b. x+14,31-54=-0,6
x=-0,6-14,31+54
x=39,09
c. x-(2×9+1)/9-(3×9+2)/9-(4×9+3)/9-(5×9+4)/9-(6×9+5)/9-(7×9+6)/9-(8×9+7)/9=100
x-19/9-29/9-39/9-49/9-59/9-69/9-79/9=100
⁹⁾x+343/9=⁹100
9x=900-343
x=557/9
x=61,(8)=61 intregi 8/9
Explicație pas cu pas:
a)
[tex]x - 12,5 = 13 \frac{1}{5} \iff x = \frac{ ^{2)} 66}{5} + \frac{125}{10} \\ x = \frac{132 + 125}{10} \iff x = \frac{257}{10} = 25,7[/tex]
b)
[tex]x + 14,31 - 54 = - \frac{3}{5} \iff x - 39,69 = - 0,6 \\ x = 39,69 - 0,6 \iff x = 39,09[/tex]
c)
[tex]x - 2\frac{1}{9} - 3\frac{2}{9} - 4 \frac{3}{9} - 5 \frac{4}{9} - 6 \frac{5}{9} - 7 \frac{6}{9} - 8 \frac{7}{9} = 100 \\ [/tex]
[tex]x = 100 + \Big(2 + 3 + 4 + 5 + 6 + 7 + 8 + \frac{1 + 2 + 3 + 4 + 5 + 6 + 7}{9}\Big) \\ [/tex]
[tex]x = 100 + 35 + \frac{28}{9} = 135 + 3 \frac{1}{9} \\ [/tex]
[tex]\implies \bf x = 138 \frac{1}{9} \\ [/tex]