Please solve this 4 marks question
Answers
Answer:
- Yes, the point (-2, -6) lies on that same line.
- The line cuts the x-axis at (2, 0).
- The line cuts the y-axis at (0, -3).
That the point (4, 3) lies on the line means that putting x=4 and y=3 makes the equation hold true. This enables us to work out the value of a:
3x - ay = 6 ⇒ 3×4 - a×3 = 6 ⇒ 12 - 3a = 6 ⇒ 3a = 6 ⇒ a = 2
So the equation of the line is
3x - 2y = 6.
The point (-2, -6) then lies on the line if putting x = -2 and y = -6 makes the equation hold true, so put these values in to check:
3x - 2y = 3×-2 - 2×-6 = -6 + 12 = 6 ✓
So yes, the point (-2, -6) lies on that same line, too.
For the coordinates of the point where the line cuts the x-axis, this is a point of the form (x, 0), where y=0. So put y=0 into the equation of the line and solve for x:
3x - 0 = 6 ⇒ x = 2 ⇒ The line cuts the x-axis at (2, 0).
Similarly, the line cuts the y-axis at a point (0, y), where x=0. So put x=0 and solve for y:
0 - 2y = 6 ⇒ y = -3 ⇒ The line cuts the y-axis at (0, -3).