# CLASS-7HORIZONTAL SUBTRACTION OF ALGEBRAIC EXPRESSION

HORIZONTAL SUBTRACTION OF ALGEBRAIC EXPRESSION

To be noted –

To add algebraic expression, collect the like terms in groups and add the terms in each group, then we have to add the unlike terms.

The negative of an algebraic expression is obtained by changing the sign of the coefficient of each term of the expression.

To subtract an algebraic expression from another, add the negative of the first expression to the second.

There are two way of subtraction an algebraic expression from another

Horizontal Method –

To subtract an algebraic expression from another, we have to add the negative of the first expression to the second, in other words we should have change the sign of each of the terms of the first expression and proceed as you would in the case of addition

Example-

1) Subtract 12xy from 85xy

Ans.)   85xy – 12xy =  73 xy            (Ans.)

2) Subtract  12ab – 9a² + 11b²   from  - 12a² + 37ab + 9b²

Ans.)   (- 12a² + 37ab + 9b² ) – ( 12ab – 9a² + 11b² )

=  - 12a² + 37ab + 9b² – 12ab + 9a² - 11b²

=    ( - 12 + 9 ) a² + ( 37 – 12 ) ab + ( 9 – 11 ) b²

=   - 3a² + 25ab – 2b²              (Ans.)

3)  Subtract  16x – 8y  from 4x² - 8x + 10y² + 12y

Ans.)    (4x² - 8x + 10y² + 12y) – (16x – 8y)

=  4x² - 8x + 10y² + 12y – 16x + 8y

=  4x² + 10y² - ( 8 + 16 )x + ( 12 + 8 ) y

=  4x² + 10y² - 24x + 20y          (Ans.)