



 
Dawn, you are right. That's a linear relation. Look for the patterns: each x increases by one for successive terms and each y decreases by 3 similarly. So you can get the value of y for any corresponding x by turning the pattern into an equation like this: When x = 1, then y = 11 (that's the starting point). But if x is larger, say 15, then it has gone up by 151 = 14 steps. So y has gone down 14 times. Each time it goes down, it drops by 3, so it goes down by 3 times 14, which is 42. Since it started at 11, it goes to 11  42 = 31. That's the same as saying "take x and subtract 1. Then multiply that by 3. Then subtract that from the starting value of y (that's 11). That's the new value of y." Turn that into an equation: "Take x and subtract 1" = x  1. y = 11  3(x  1). This simplifies: y = 14  3x. Check it with x = 15. What value of y were you expecting? Hope this helps,  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 