| --- |
| source: ncert_exercises |
| topic: algebra |
| class_level: class_9 |
| chapter: ch4 |
| exercise: ex4.4 |
| difficulty: beginner |
| --- |
| |
| Class 9 | Ch4: Linear Equations in Two Variables | Exercise 4.4 |
|
|
| Q1. Give geometric representations of y=3 as equation: |
| (i) in one variable (ii) in two variables |
| Answer: |
| (i) In one variable (on number line): y=3 is a single point at 3 on the number line. ✅ |
| (ii) In two variables: 0x+y=3. Graph is a horizontal line parallel to x-axis, passing through (0,3). ✅ |
|
|
| Q2. Give geometric representations of 2x+9=0 as equation: |
| (i) in one variable (ii) in two variables |
| Answer: |
| (i) In one variable: 2x+9=0 → x=-9/2=-4.5. Single point at -4.5 on number line. ✅ |
| (ii) In two variables: 2x+0y+9=0. Graph is a vertical line parallel to y-axis, passing through (-9/2, 0) = (-4.5, 0). ✅ |
|
|
| Key rules for graphs: |
| - y=k (constant): horizontal line parallel to x-axis at height k. |
| - x=k (constant): vertical line parallel to y-axis at distance k. |
| - y=0: the x-axis itself. |
| - x=0: the y-axis itself. ✅ |
