Question

{[(107 - 63 : X ) x 9 - 2] : 5 + 3 x 9 } x 4 - 12 = 800

Answer 1

{[(107-63:x)x9-2]:5+27}x4=800+12
{[(107-63:x)x9-2]:5+27}x4=812
{[(107-63:x)x9-2]:5+27}=812:4
{[(107-63:x)x9-2]:5+27}=203
[(107-63:x)x9-2]:5=203-27
[(107-63:x)x9-2]:5=176
[(107-63:x)x9-2]=176x5
[(107-63:x)x9-2]=880
(107-63:x)x9=880+2
(107-63:x)x9=882
(107-63:x)=882:9
(107-63:x)=98
63:x=107-98
63:x=9
x=63:9
x=7