1) (43+y)-61=115
43+y-61=115
-18+y+115
y=115+18
y=133
2) 718-(25+t)39
718+(-25-t)39
718-975-39t
-257-39t
3) (a-97)+325=444
a-97+255=444
a=444-255
a=189
4) 24(x-9)=1080
x-9=45
x=45+9
x=54
5) (5+b)2=10004
10+2b=10004
2b=10004-10
2b=9994
2=4997
6)(433-c):9=223
433-c
-------- = 223
9
433-c=2007
-c=2007-433
c= -1574
7) 1836:(p-4)=918
1836
------- =918
p-4
1836
------- =918, p≠4
p-4
1836=918(p-4)
1836=918p-3672
-918p=-3672-1836
-918p=-5508
p=6, p≠4
p=6
8) 15y+43=1573
15y=1573-43
15y=1530
y=102
9)63-5z=28
-5z=28-63
-5z=-35
z=7
10) 91-81=18
10≠18