Question

{13+[25*4-(3*11+3*22)]*m} /2=13

Answer 1

{13+[25x4-(3x11+3x22)]xm} /2=13
{13+[100-(33+66)]xm}/2=13
[13+(100-99)xm]/2=13
(13+1xm)/2=13
(13+m)/2=13
13+m=13x2
13+m=26
m=26-13
m=13

Answer 2

{13+[25*4-(33+66)]*m}=13*2  
{13+[25*4-(33+66)]*m}=26
[13+(100-99)*m]=26
13+1*m=26
13+m=26
m=26-13
m=13