# Finding Intercepts From an Equation

## Equation of a Line Passing Through Two Points

### Intercepts Y

The y-intercepts are actually the points where the graph of a function or an equation “touches” or passes through the y-axis in the Cartesian Plane. You may also consider this as a point having x-value of zero.

In order to determine the y-intercepts of an equation, let x = 0, then solve for y.

In a point notation, it is expressed as (0,y)

### How to Find the X-Intercepts

Just like the y-intercept, the x-intercepts are basically the points where the graph of a function or an equation “touches” or passes through the x-axis of the Cartesian Plane. Imagine this as a point with y-value of zero.

In order to find the x-intercepts of an equation, let y = 0, then solve for x.

In a point notation, it is expressed as (x, 0).

### Finding Intercepts Equation

Let’s first learn how to Find the x and y-intercepts of the general form equation of a line y = –2x + 4.

In order to identify the x-intercepts algebraically, we let y=0 in the equation and then solve for x. Likewise, to find the intercept y algebraically, we let x=0 in the equation and then solve for values of y.

 X – Interceptlet y=0 then solve for x Y – Interceptlet x=0 then solve for y Y = -2x + 4 Y = -2x + 4 0 = -2x + 4 0 = -2(0) + 4 0 – 4 = -2x + 4 - 4 Y = 0+4 -4 = -2x Y = 4 -4/-2= -2x/2 2x Written as point; (2,0) Written as point; (0,4)

Below is the graph to verify our answers are correct. ### How to Find the X and Y-Intercepts of the Quadratic Equation

Let's learn how to determine x and y-intercepts of the quadratic equation. Consider a quadratic equation: y = x² − 2x − 3.

Now, the graph of this quadratic equation will be in the shape of a parabola. We assume it to have a “U” shape in which it would either open up or down.

In order to solve for the x-intercept of this problem, we would require factoring a simple trinomial. Then you set each binomial factor equivalent to zero and solve for value of x.

 X – Interceptlet y=0 then solve for x Y – Interceptlet x=0 then solve for y Y = x² -2x -3 Y = x² -2x -3 0 = x² -2x -3 0 = (0)² -2 (0) -3 0 = (x+1) (X-3) = 0 – 0 -3 X1 = -1, X2 = 3 Y = -3 as points; (-1,0) and (3,0) as points; (0,-3)

### Below are our solved values for both x and y-intercepts that match along with the graphical solution. ### Solved Examples

Example:

Find the intercept of the given function

Determine the intercepts of the equation given as; y=-3x - 4. Then plot the graph with the help of only the intercepts.

Solution:

Set y=0 in order to find out the x-intercept.

y=−3x−4

0=−3x−4

4=−3x

-4/3 = x

= (−4/3) = 0 x intercept

Set y=0 in order to find out the y-intercept.

y=−3x−4

y=−3x(0)−4

y= -4

4=−3x

-4/3 = x

=(0, -4)y intercept

Now, let’s plot both x and y intercept slope intercept form, and draw a line crossing through them as in the figure shown below: 