Whats the answer to this?? And how did you get the answer.. ( what methods)??

Question

Which of the following pairs of points both lie on the line whose equation is 3x-y= 2?
(2,-2) and (1,5)
(2,4) and (1,5)
(2,4) and (3,7)
(3,-2) and (1,5)
(3,7) and (3,-2)

ok come on math Geniuse's lol..... whats the answer :P

Answer 1

I think the answer has appeared above, but just wanted to throw in my 2 cents.

The main thing to remember when presented with an equation such as the one above, is to solve it for one variable. Since most lines are based on y = equations, simply solve for y, from the equations 3x - y = 2. Basically move the y to right right hand side by adding y to both sides: 3x - y (+ y) = 2 (+ y) Because you are adding the same amount to both sides, you're not changing the solution at all. Next, subtract 2 from both sides, so you equation looks like: 3x - y ((+ y) (- 2)) = 2 ((+ y) (- 2)) The parantheses here do not imply multiplication. Now, cancel the areas that = 0.

Final equation: 3x - 2 = y.

Now, plug in your points to solve. If x = 2, then 3 * 2 - 2 = y. Here, y = 4. Now you know your first point.

Does this make sense?

When doing any equations like this, remember it's OK to move variables around & multiply or divide as long as you do the same to both sides of the equation.

Good luck.

Answer 2

The answer is (2,4) and (3,7). Substitution is the method. Plug in 2 for x and 4 for y, and you get 3*2 - 4 = 2, correct. Plug in 3 for x and 7 for y and you get 3*3 -7 = 2, which is also correct. Easiest and simplest way when given such a small sample and simple equation.

Answer 3

Hopefully I can explain this...first you need to change the equation so it is in the format: y = mx+b. To do this, add y to both sides and subtract 2 from both sides. Your new equation will be: y = 3x -2. Now, if you have a graphing calculator you can type this into y = and look for those points on the graph or in the table. Another way, is to just plug in those points for x and y until you find which points fit the line. Its a longer process, but not too difficult. Hope I helped.

Answer 4

you just have to subsitute the x coordinates of the ordered pairs with the x in the equation and the y coordinates of the ordered pairs with the y in the equation.
the answer is :
(2,4) and (3,7)

Answer 5

Substitute in the points.

Answer 6

I know the answer, but I'm too hypnotised by your cleverly cute avatar picture.