(100 - x :76)*35 + 1=876
(100-x:76)×35=876-1
(100-x:76)×35=875
100-x:76=875:35
100-x:76=25
x:76=100-25
x:76=75
x=76×75
x=5700
[(100+x): 75 - 1)]*35=875
(100+x):75-1=875:35
(100+x):75-1=25
(100+x):75=25+1
(100+x):75=26
100+x=26×75
100+x=1950
x=1950-100
x=1850