Explanation for Question 5 From the Math (No Calc) Section on the Official Sat Practice Test 6
All right. So this question asks us, 2 which of the following is the graph of the equation. 3 Y equals two X minus five in the X, 4 Y plane. So let's write this out a little bigger to the side, 5 and hopefully this looks familiar and it is indeed in slope intercept form, 6 which is Y equals MX plus B. 7 Now thinking back M is going to be equal to the slope. 8 So that's how fast the graph rises. 9 And that's also known as rise overrun, 10 and then B is equivalent to the Y intercept. 11 So that's why, or that's where the graph crosses the Y 12 axis. 13 So that y-axis is going to be right here. And that Y intercept would 14 be wherever that intersection falls. So like right here for this, 15 this graph. All right. 16 So first what we can do is we can look at that Y intercepts 17 and see which of these graphs cross the Y axis at Y 18 or at Y is equal to negative five. 19 So looking at that point, right there, Y is equal to negative five. 20 We can cross out a and C, we see that B and D both 21 cross at negative five. Now looking at the slope, 22 we see the slope is two X. 23 So this is positive, which means that it grows in the positive direction as 24 X increases, Y increases as well. So we can pick D from there because 25 D is the only one with a positive slope. Another way to confirm if 26 both of the slopes have been positive is you can see it. 27 The slope is two X. If you pick out two hypothetical points. 28 So thinking about the fact that slope equals rise over run in this case, 29 the slope or the rise is two. 30 It goes up one, two over a run of just one. 31 So just one, that's how we get the slope is equal to two, 32 and that this does indeed fit the Y equals two X minus five.