Linear Simultaneous
1. Stating the problem: We need to plot the graph of the simultaneous linear equations:
$$y - 2x = 5$$
$$2y + x = 0$$
2. Find the intercepts for the first equation $y - 2x = 5$:
- For the y-intercept, set $x=0$:
$$y - 2(0) = 5 \\ y = 5$$
- So, the y-intercept is $(0, 5)$.
- For the x-intercept, set $y=0$:
$$0 - 2x = 5 \\ -2x = 5 \\ x = -\frac{5}{2} = -2.5$$
- So, the x-intercept is $(-2.5, 0)$.
3. Find the intercepts for the second equation $2y + x = 0$:
- For the y-intercept, set $x=0$:
$$2y + 0 = 0 \\ 2y = 0 \\ y = 0$$
- So, the y-intercept is $(0, 0)$.
- For the x-intercept, set $y=0$:
$$2(0) + x = 0 \\ x = 0$$
- So, the x-intercept is also $(0, 0)$.
4. Interpretation:
- The first line intercepts the y-axis at $(0, 5)$ and the x-axis at $(-2.5, 0)$.
- The second line intercepts both axes at the origin $(0,0)$.
5. Using these points, you can plot the two lines and find their point of intersection graphically.
6. To find the exact solution algebraically:
- From the second equation: $$2y + x = 0 \Rightarrow x = -2y$$
- Substitute into the first: $$y - 2(-2y) = 5 \Rightarrow y + 4y = 5 \Rightarrow 5y = 5 \Rightarrow y = 1$$
- Then $$x = -2(1) = -2$$
7. So, the solution where the two lines intersect is $(-2, 1)$.
Final answer:
- First line intercepts at $(0,5)$ and $(-2.5,0)$.
- Second line intercepts at $(0,0)$.
- Intersection point is $(-2,1)$.