Explanation for Question 35 From the Math (Calc) Section on the Official Sat Practice Test 6
Question 35 asks us the line with the equation. 2 Four fifths X plus one third. Why is equal to one is graft in 3 the X, Y plane. What does the X coordinate of the X intercept of 4 the line? Okay. 5 So let's draw a picture so we can understand what's happening more. 6 Clearly we have some line somewhere. 7 We don't know where, and we don't know what it's soap is, 8 and we don't know where it intercepts, but that's okay. 9 All we need to find out is the X coordinate of the X intercept 10 of the line. So the X intercept is where the line is going to 11 cross the X axis. 12 So this being X and the speed Y and when the X intercept 13 occurs, Y is equal to zero, 14 as you can see. So let's just plug in Y is equal to zero 15 and see what X we're left up with, or we'll end up with. 16 So we have four fifths X plus one third. 17 Why with Y being zero is equal to one. 18 We have four fifths, 19 X plus zero is equal to one. 20 So then we have four fifths. X is equal to one. 21 Now what we can do is we can multiply both sides by five over 22 four, and that will cancel out the four fifths on this side. 23 And that will leave us with X is equal to five over four. 24 So the X coordinate of the X intercept of the line is X is 25 equal to five, over four.