Question

{[(9x3xa-79}x61-78]x15+340}:250=36:9

Answer 1

[(27a-79)x61-78]x15+340=4x250
[(27a-79)x61-78]x15=1000-340
(27a-79)x61-78=660:15
(27a-79)x61=44+78
27a-79=122:61
27a=2+79
a=81:27
a=3

Answer 2

{[(9×3×a-79)×61-78]×15+340}:250=36:9
{[(27a-79)×61-78]×15+340}:250=4
[(27a-79)×61-78]×15+340=4×250
[(27a-79)×61-78]×15+340=1000
[(27a-79)×61-78]×15=1000-340
[(27a-79)×61-78]×15=660
(27a-79)×61-78=660:15
(27a-79)×61-78=44
(27a-79)×61=44+78
(27a-79)×61=122
27a-79=122:61
27a-79=2
27a=79+2
27a=81
a=81:27
a=3