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Linear Equations in Two Variables
Chapter summary, hard words and model exam answers for Class 9 Hindi.
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Maths · ICSE Class 9
Summary
A linear equation in two variables has x and y, and the powers of both variables are 1. A common form is ax + by + c = 0, where a and b are not both zero.
A solution is an ordered pair (x, y) that makes the equation true. Since one value can often be chosen freely, a linear equation in two variables has infinitely many solutions.
To check whether a point lies on a line, substitute its x-coordinate and y-coordinate in the equation. If LHS equals RHS, the point lies on the line.
Choose convenient values of x, calculate y, and write ordered pairs. Plot at least two points, preferably three for checking, and join them with a straight line.
The x-intercept is where the graph cuts the x-axis, so y = 0. The y-intercept is where the graph cuts the y-axis, so x = 0.
Let x and y stand for the two changing quantities. Translate the sentence into an equation, then use substitution, a table or a graph to answer the question.
Hard words & meanings
| linear equation | An equation whose graph is a straight line |
| two variables | Two unknown quantities, usually x and y |
| solution | A value or ordered pair that makes an equation true |
| standard form | A common form ax + by + c = 0 |
| x-intercept | The point where a graph meets the x-axis |
| y-intercept | The point where a graph meets the y-axis |
| infinitely many | More than any fixed count; continuing without end |
Model exam answers, grammar & audio
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