Question

[(40-a):5×7+25]:6=10

Answer 1

[(40-a):5×7+25]:6=10
[(40-a):5×7+25]=10×6
(40-a):5×7=60-25
(40-a):5 =35:7
40-a =5×5
40-a=25
a = 40-25
a= 15

Answer 2

[40-a/5×7+25]×1/6=10,
[7×40-a/5+25]×1/6=10,
[280-7a/5+25]×1/6=10,
280-7a+125/5×1/6=10,
405-7a/30=10,
405-7a=300,
-7a=300-405,
-7=-105,
a=15.