[Video] Q8: The line y k = +4 x , where k is a constant, is graphed in the xy-plane. if the line contains the point (, ) c d , where c ≠ 0 and d ≠ 0, what is the slope of the line in terms of c and d ?

Explanation for Question 8 From the Math (No Calc) Section on the Official Sat Practice Test 3

Now for number eight, we're looking at a line Y equals K X plus 2 four, where K is a constant. 3 That just means that K is a normal number. 4 And that K will usually be the same number, 5 um, throughout the entire problem. Um, 6 and it's graft, right? And so the line contains the point C comma D 7 where C is not equal to zero and D is not equal to zero. 8 So all that means is that the point exists somewhere here, 9 here, or here, but not on either of our, 10 uh, axes, right? Not on the Y axis or the X axis. 11 And so it wants to know what is the slope of the line in 12 terms of C and D? Right? 13 So essentially we have a point C comma D where 14 C is like our X value in D is like our Y value. 15 So we can take this equation that they've given us. 16 And instead of writing X and Y we can put plug in C and 17 D, right? So D was my Y C was my ex and I'm here. 18 And we know that whatever the coefficient is on X is always our 19 slope, right? So essentially we want to solve for K here so that we 20 can solve for the slope of the line. A good first start is going 21 to be to subtract four from both sides. That way these fours will cancel. 22 I am left with K time seat, and now I just need to divide 23 both sides by C so that I get K alone. 24 Right. So K is equal to D minus four oversea, 25 and we can see that here in answer choice. Okay. 26 So the best way to go about this problem was to use the equation 27 of the line to solve for the slope, which was our variable. 28 Okay.