Find two numbers whose sum is 138 and whose difference is 88

X + y = 138
x - y = 88

x + y = 138
-x   
      y = -x + 138

-> substitute " -x + 138" into y
x- (-x+138) = 88
x + x - 138 = 88
2x - 138 = 88
    + 138
2x = 226
2x/2 = 226/2
x= 113

-> substitute "113" into x to get y
113 - y = 88
-113         -113
-y= -25
y = 25

Our final answers are the two numbers "113" and "25"

Direct variation is
y=kx
subsitute
-6=-36k
diivde both sdies by -36
1/6=k

the equation is
y=1/6x or B