x- and y-intercepts of a line, step by step
Where a line crosses each axis is one substitution away: at the x-axis y is zero, at the y-axis x is zero.
The question
the x-intercept of x + 9y = −9
x + 9y = −9y = 0
x = −9
x = −9
- The x-intercept is where the line crosses the x-axis, and there y = 0. Put y = 0 into x + 9y = −9.
- The y-term disappears, leaving x = −9.
- So the x-intercept is −9.
How it works.
- 01
The x-intercept is where the line crosses the x-axis, and there y = 0. Put y = 0 into x + 9y = −9.
- 02
The y-term disappears, leaving x = −9.
- 03
So the x-intercept is −9.