# GMAT Math : Calculating whether point is on a line with an equation

## Example Questions

### Example Question #61 : Coordinate Geometry

Solve for  in the coordinate  on line ?

Explanation:

To solve for  for , we have to plug  into the  variable of the equation and solve for :

### Example Question #68 : Coordinate Geometry

Solve for  in the coordinate  on line ?

Explanation:

To solve for  for , we have to plug 1 into the  variable of the equation and solve for :

### Example Question #71 : Coordinate Geometry

Solve for  in the coordinate   on line ?

Explanation:

To solve for  for , we have to plug  into the  variable of the equation and solve for :

### Example Question #72 : Coordinate Geometry

Consider segment  which passes through the points  and .

If the point  is on , what is the value of y?

Explanation:

First, use the points to find the equation of JK:

Given that JK passes through (4,5) and (144,75) we can find the slope as follows:

Slope is found via:

Plug in and calculate:

Next, we need to use one of our points and the slope to find our y-intercept. I'll use (4,5).

To find y, we need to plug in 16 for x and solve:

### Example Question #71 : Coordinate Geometry

If  is defined as follows, is the point on ?

Yes

f(x) is undefined at (-2,5)

No

Cannot be calculated from the provided information

Yes

Explanation:

To find out if (-2,5) is on f(x), simply plug the point into f(x)

Becomes,

So yes, it does!

### Example Question #74 : Coordinate Geometry

Which of the following are points along  if

.

Explanation:

One way to solve this one is by plugging in each of the answer choices and eliminating any that don't work out. Begin with our original g(x)

If we plug in 3 we get

So our point is (3,28).

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