Question

How do you find the x and y intercept of $3x + 6y = 24$?

Answer 1

x-intercept can be found by substituting the value of ‘y’ is equal to zero in the given equation. Similarly we can find the y-intercept by substituting the value of ‘x’ equal to zero in the given equation. In other words ‘x’ intercept is defined as a line or a curve that crosses the x-axis of a graph and ‘y’ intercept is defined as a line or a curve crosses the y-axis of a graph.

Complete step-by-step solution:
Given, $3x + 6y = 24$.
To find the ‘x’ intercept put $y = 0$ in the above equation,
$\Rightarrow 3x + 6(0) = 24$
$\Rightarrow 3x = 24$
Divide by 3 on both sides of the equation,
$\Rightarrow x = \dfrac{{24}}{3}$
$\Rightarrow x = 8$.
Thus ‘x’ intercept is 8.
To find the ‘y’ intercept put $x = 0$ in the above equation,
$\Rightarrow 3(0) + 6y = 24$
$\Rightarrow 6y = 24$
Divide by 6 on both sides of the equation,
$\Rightarrow y = \dfrac{{24}}{6}$
$\Rightarrow y = 4$.
Thus ‘y’ intercept is 4.
If we draw the graph for the above equation. We will have a line or curve that crosses the x-axis at 8 and y-axis at -4.

Note: We can solve this using the standard intercept form. That is the equation of line which cuts off intercepts ‘a’ and ‘b’ respectively from ‘x’ and ‘y’ axis is $\dfrac{x}{a} + \dfrac{y}{b} = 1$. We convert the given equation into this form and compare it will have a desired result.
Given $3x + 6y = 24$
Now we need 1 on the right hand side of the equation, so divide the whole equation by 24. We have,
$\Rightarrow \dfrac{{3x + 6y}}{{24}} = \dfrac{{24}}{{24}}$
Splitting the terms we have,
$\dfrac{{3x}}{{24}} + \dfrac{{6y}}{{24}} = \dfrac{{24}}{{24}}$
That is we have,
$\Rightarrow \dfrac{x}{8} + \dfrac{y}{4} = 1$. On comparing with standard intercept form we have ‘x’ intercept is 8 and y intercept is 4. In both the cases we have the same answer.