Explanation for Question 15 From the Math (Calc) Section on the Official Sat Practice Test 4
Now hearing number 15, we're looking at which of the following scatterplots shows a 2 relationship that is appropriately modeled with the equation, 3 M a X to the B, 4 where a is positive and B is a negative. 5 So essentially what we're seeing right off the bat is that this has an 6 exponent, right? An exponent create lines that have curves either 7 upward or downward. They don't create actual lines. 8 Rather they, they create curves. It wouldn't be good to call these lines. 9 Um, and so if we're looking at something with the exponent, 10 we should know that any graph that has a linear looking, 11 you know, set up should be off the table. Right? 12 So a appears to be constant B seems to have some curve to it. 13 So we'll keep it C seems to have some curve to it and is 14 all over the place. So we can probably eliminate D two because an exponent 15 would create a trend upward or downward we're unsure of at the moment, 16 but this graph has no trend and the exponent would, 17 would show something more obvious than this. 18 So now we're told a is positive, which essentially means that we have a 19 positive starting point. For example, 20 two, we'll just come up with example numbers right now. 21 And then we have a negative exponent. 22 Let's call it, you know, uh, X to the negative one. 23 Okay. So if we have a positive starting point that it should make sense 24 that our graph will start somewhere positive, which we see in both. 25 But what about the exponent does having a nega...