Question

105:3+4-{4+ [13+ 5x (8-5xa)]:4=28​

Answer 1

$105:3 + 4 - \{4 + [13 + 5 \cdot (8 - 5 \cdot a)] : 4\} = 28$

$35 + 4 - \{4 + [13 + 5 \cdot (8 - 5 \cdot a)] : 4\} = 28$

$39 - \{4 + [13 + 5 \cdot (8 - 5 \cdot a)] : 4\} = 28$

$4 + [13 + 5 \cdot (8 - 5 \cdot a)] : 4 = 39 - 28$

$4 + [13 + 5 \cdot (8 - 5 \cdot a)] : 4 = 11$

$[13 + 5 \cdot (8 - 5 \cdot a)] : 4 = 11 - 4$

$[13 + 5 \cdot (8 - 5 \cdot a)] : 4 = 7$

$13 + 5 \cdot (8 - 5 \cdot a) = 7 \cdot 4$

$13 + 5 \cdot (8 - 5 \cdot a) = 28$

$5 \cdot (8 - 5 \cdot a) = 28 - 13$

$5 \cdot (8 - 5 \cdot a) = 15$

$8 - 5 \cdot a = 15 : 5$

$8 - 5 \cdot a = 3$

$5 \cdot a = 8 - 3$

$5 \cdot a = 5$

$a = 5 : 5$

$\implies \bf a = 1$