What's the rule the function machine using, input 22,output 12,input 23,output 16,input 24,output 20,input 25,output24,input 26,output 28

Answer 1

in 22 23 24 25 26 <--- the x's
out12 16 20 24 28 <--- the y's

did you notice that for every increase of 1 in your x, the y increases by 4 ?

so we have y = 4x + b
plug in (22,12)
12 = 4(22) + b
b = -76

rule: y = 4x - 76

test it for some of the given values, it works!