Revision: Simultaneous (Linear) Equations [Including Problems] Mathematics (English Medium) ICSE Class 9 CISCE

• Some equations are not linear in the given variables.

• By a suitable change of variables, they can be reduced to linear equations.

• After substitution, the equations become linear in the new variables.

• Denominators must not be zero.

Simultaneous Linear Equations: Two linear equations solved together.

Elimination method:

1. Make the coefficients equal
2. Add/subtract 
3. Find one variable
4. Substitute to get the other.

Substitution method:

1. Express one variable in terms of the other, 
2. Substitute 
3. Solve 
4. Substitute back.