9C

Intercepts and graphical solutions

Finding the x- and y-intercepts of a line, sketching with intercepts, and solving equations or pairs of equations from where lines meet.

Intercepts

Example 1●

Find the intercepts of $y = 2x - 6$.

$x = 0$: $y = -6$.
$y = 0$: $2x = 6$, so $x = 3$.

Where lines meet

Point of intersection

The meeting point satisfies both equations at once.

Example 2●●

Where do $y = x + 1$ and $y = -x + 5$ meet?

$x + 1 = -x + 5$, so $2x = 4$ and $x = 2$.
$y = 3$. They meet at $(2, 3)$.
Flashcards
$y$-intercept
Set $x = 0$.
$x$-intercept
Set $y = 0$.
Where two lines meet
The point that satisfies both equations.
Practice
  1. Find the $x$-intercept of $y = 2x - 6$.

  2. Find the $y$-intercept of $y = 2x - 6$.

  3. Where do $y = x + 1$ and $y = -x + 5$ meet? Enter $x, y$.

  4. Find the $x$-intercept of $y = 8 - 2x$.

  5. Find the $x$-intercept of $x + y = 5$ as a point. Enter $x, y$.

  6. Find the $y$-intercept of $2x + 3y = 9$.

  7. Where do $y = 3x + 1$ and $y = x + 3$ meet? Enter $x, y$.

  8. A graph of $y = 2x - 1$ crosses $y = 5$ at $x = 3$. This means:

More questions

New numbers every time. Keep going until you get five in a row.

Formula sheet