Explanation for Question 9 From the Math (No Calc) Section on the 2019 October Sat
So here for number nine, we're told that the table shown gives some values 2 of X and the corresponding values of F of X, 3 where F is a linear function. So that's important to know the F is 4 aligned, which means that it will have a slope, right. 5 And a Y intercept. And then we're told that Y is equal to F 6 of X is graft in which of the following would be the Y intercept. 7 Right? And so if we see Y intercept, 8 the first thing we should, uh, think is, 9 okay, do they give me a point where X is equal to zero? 10 Because if they told me where X is equal to zero, 11 that would show me my Y intercept because Y intercepts always happen at the 12 Y axis where X is equal to zero. 13 Now, if we look at this table that they've given us, 14 we don't see any zero values for X. 15 So we're going to have to do a little bit more work and probably 16 the most, uh, full-proof and efficient way to do that work is going to 17 be, to use an equation, 18 MX plus B, and solve for B the y-intercept. 19 Now in order to solve for B, we need first off an X and 20 a Y, which we have actually right up here. 21 We have X and Y values in the table, but we also need the 22 slope. So what I need to do now is take the two points that 23 were given me in this table. I'll call the top point 0.1, 24 then the bottom point, 0.2 and use those points to solve for my slope. 25 And we can use the equation. The slope is equal to Y two minus 26 Y one over X two minus X one. 27 So now I'm just going to plug and chu...