Find the x- and y-intercept of the line. -3x + 9y = 18

Solution:

The x-intercept is the value of x coordinate where a line cuts the x-axis, and the y-intercept is the point where the line cuts the y-axis.

First method:

Given equation is -3x + 9y = 18

Divide the equation by 18 throughout

(x/-6) + (y/ 2) = 1 compare with (x/a) + (y/b) = 1 where a is x intercept and b is y intercept

Hence x - intercept is = -6 and y - intercept = 2

Second method:

Given equation is -3x + 9y = 18, now we know that x and y intercepts are the points on x and y axis respectively.

Thus to get the x - intercept put y = 0 in the given equation

∴ -3x + 9(0) = 18 ⇒-3x = 18 ⇒ x = -6 ⇒ x intercept = -6

And to get the y intercept put x = 0 in the given equation,

∴ -3(0) + 9y = 18 ⇒ 9y = 18 ⇒ y = 2 ⇒ y intercept = 2

Also from the graph it is clear that x-intercept and y- intercept of the given line are (-6, 2) respectively.

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Find the x- and y-intercept of the line. -3x + 9y = 18

Summary:

The x- and y-intercept of the line. -3x + 9y = 18 are -6 and 2 respectively.