<p>I know how to use my graphing calculator so I could use the INTERSECT option in it, but I came across a problem where I couldn’t use the calculator so easily. I can’t remember it in detail, but it was like y=-1/3x +b and y=3x(I don’t know if these are the exact equations or not)and they intersect at (t, t+1), and they asked me for the value of ‘t’. The only thing I could do was to keep trying random #s for “b” but that would take too much time so I skipped it and still couldn’t figure it out when I had time left over.</p>
<p>mmm, well generally finding the intersection of 2 lines is basically solving a system of linear equations involving two variables.</p>
<p>now the place where they intersect is the solution to the system, in other words (x, y) must hold true for both equations. so when it says it intersects at (t, t+1), you would plug t in for x, and t+1 in for y and go from there. They were probably asking for b, which you could substitute or eliminate to get the value of.</p>
<p>B was a constant, sorry I should have put that in before.</p>
<p>t would be 1/2 if you just plug (x,y) into y=3x.</p>
<p>Or, if you have a graphing calculator, just graph them. On models such as the TI-83, there is a “calculate intersect” operation which requires only about 5 seconds. Assuming you type in the two functions correctly, it’s generally faster than computing and bears no margin of error.</p>
<p>To Godfather, you can’t graph y=-1/3x + b. I know about that intersect feature and a lot of different things about graphing on the calculator thanks to my PreCalculus Teacher. Knowledge of the calculator alone can help you answer some of the hardest questions. I just graph these lines and find the answers so easily. If I ever get something like x=y^2+4, at first I might be stumped. but then you can solve for Y and get to different values for X(one negave and positive square root), and then you just graph those two different lines. Do all the 700+ Math people here get by on their tests without graphing on their calculator?</p>
<p>lol i think that’s why im good at the math… all i do is plug-in, guess and check, and/or graph on calculator… so much of the math sections are like that.</p>
<p>Those questions which ask you to pick a graph when given an equation are so easy! I agree, plugging in your own numbers and substituting the answer choices also help. You don’t need, but you really really SHOULD have a graphing calculator, and KNOW HOW TO USE IT right to answer these questions. My teachers have taught me all about them last year. I didnt’ know how to make a fraction by itself(put it in parenthesees) or do an x root of a #(raise the # to the reciprocal of “x”). If you know all these strategies and methods, you should be in good condition for the math section.</p>