835-11*r=758x*12+18=90

Question

835-11*r=758
x*12+18=90

Answer 1

x*12+18=90
12х=90-18
12х=72
х=72:12
х=6

835-11*r=758
11r=835-758
11r=77
r=77:11
r=7

Answer 2

835-11r=758
-11r=758-835
-11r=-77
r=-77/(-11)
r=7

12x+18=90
12x=90-18
12x=72
x=72/12
x=6