So for the first one... Let's just use x for months and m for minutes.
(20m)+(.15m)
20 times the number of months plus .15 times the number of minutes
Same for the next one
(35x)+ (.10m)
35 times the number of months +.10 times the minutes.
Each means to multiply I dont know if thats the word you are asking to us to define
maybe xd ad something else please
X/2-y/3=3/2
(6×x/2)-(6×y/3)=6×3/2
3x-2y=9______(1)
x/3+y/2=16/3
(6×x/3)+(6×y/2)=6×16/3
2x+3y=32_____(2)
(1)×3____9x-6y=27____(3)
(2)×2____4x+6y=64____(4)
(3)+(4)___13x=91
x=7
3(7)-2y=9
-2y=-12
y=6
If you start from a temperature of -6° C and you need to lower that temperature of 20 more degrees, you have to subtract:

So, the temperature in Antarctica is -26° C