LAMathematics

MP Board · Class 10 · Mathematics · Pair of Linear Equations in Two VariablesExplain the method of elimination and substitution for solving a pair of linear equations in two variables. Provide a suitable example to illustrate your answer.

Step-by-Step Solution

Method of Elimination\nThe method of elimination is a technique used to solve a pair of linear equations in two variables. It involves adding or subtracting the equations to eliminate one of the variables.

Step 1: Write the equations in the standard form\nax + by = c\ndx + ey = f

Step 2: Multiply the equations by necessary multiples such that the coefficients of y's in both equations are the same\na'x + b'y = c'\nd'x + e'y = f'

Step 3: Subtract the second equation from the first equation

(a' - d')x = c' - f'

Step 4: Solve for x\nx = (c' - f') / (a' - d')

Step 5: Substitute the value of x in one of the original equations to solve for y\nax + by = c\na((c' - f') / (a' - d')) + by = c

Example\nSolve the pair of linear equations: 2x + 3y = 7 and x - 2y = -3.

Step 1: Write the equations in the standard form

2x + 3y = 7\nx - 2y = -3

Step 2: Multiply the equations by necessary multiples such that the coefficients of y's in both equations are the same

2x + 3y = 7\nx - 2y = -3

Step 3: Subtract the second equation from the first equation

(2x + 3y) - (x - 2y) = 7 - (-3)\nx + 5y = 10

Step 4: Solve for x\nx = (10 - 5y) / 1\nx = 10 - 5y

Step 5: Substitute the value of x in one of the original equations to solve for y

2x + 3y = 7 2(10 - 5y) + 3y = 7 20 - 10y + 3y = 7 -7y = -13\ny = 13/7

Conclusion\nThe solution of the given pair of linear equations is x = 10 - 5y and y = 13/7.

💡 Study Guide: This question tests core syllabus concepts from Pair of Linear Equations in Two Variables. For formulas, key summaries, and mock exam reference guides, read the full Pair of Linear Equations in Two Variables Revision Notes.
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