Which of the points (0, -7) (2,3) (1,8) (3,1) is a solution for y=-2x+7?

Question

Solution of the equation.

Answer 1

In order to know whether a point is a solution for the equation, you must take the x-coordinate from the point and plug it into equation. If the answer you get does NOT equal the y-value on the point, then it is NOT a solution. If the y-value is the same, then you have solved it.

 

For Example:

 

Let's say I have the equation y = 5x -2

 

If I wanted to know if (2,1) was a solution for the equation, I would plug '2' into the equation for the x-value.

 

y = (5)(2) -2

 

When I solve this, I find that y = 8. 

 

Since the y-value on my point does NOT equal 8, then I know that (2,1) is not a point along that line.

Answer 2

You must do this yourself.  substitute 0 in for x, and see what y value comes out; if it's -7, then that first ordered pair is a solution (point on the graph).

 

repeat for the next pair (substitute 2 for x, see if y comes out to be 3.

 

Et cetera, et cetera...it's possible that more than one of these is a solution, so test all of them.