MathematicsClass 8Linear Equations in One Variable

Reducing Equations to Simpler Form

Simplifying complex linear equations into standard forms before solving them.

Class 8 · MathematicsCBSE & ICSE SOF IMO

Definition

Sometimes linear equations are presented in complex forms involving parentheses, fractions, or decimals. Reducing them involves clearing fractions by multiplying by the LCM of the denominators, expanding brackets using distributive laws, and clearing decimals. After these steps, the equation transforms into a standard linear form that is easy to solve.

Key formula

(x + a)/b = (cx + d)/e

Worked examples

1

Solve (x - 5)/3 = (x - 3)/5: Cross-multiply to get 5(x - 5) = 3(x - 3), expand to 5x - 25 = 3x - 9, which gives 2x = 16 or x = 8.

2

Solve 3(t - 3) = 5(2t + 1): Expand to 3t - 9 = 10t + 5, transpose to get -7t = 14, so t = -2.

3

Solve x/2 - 1/5 = x/3 + 1/4: Multiply the entire equation by the LCM of denominators (60) to eliminate fractions.

Common mistakes

  • Multiplying only the numerator and forgetting to multiply the denominator when clearing fractions.
  • Applying the distributive property to only the first term inside the parentheses instead of all terms.
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