Page 111 - Maths Skills - 8

Linear Equations in One Variable 109

3. Devesh’s school is 15 km from his home. He covers this distance in 3 hours, partly by walking and partly
by cycling. If he walks at 3 km/h and cycles at 9 km/h; how much distance does he cover by cycling?

4. Complete the magic square using linear equations so that the sum of 42 140 77
each row, column and diagonal is equal.
133 98

56 126

119 49 112

Word Stock
Linear Equation Variable Solution Consecutive Balance
Transposition Root Interchange Exceed Statement Substituting

Activity

Objective: To understand multiplication of binomial with a binomial, i.e. (x + 5) (x + 3).

Pre-Requisite Knowledge: Concept of linear equations.
Materials Required: Square cards with side x, strips with length x units and width 1 unit, small squares with side
1 unit.

Procedure: 1. Take a square of side x units. It represents an area of x .
2
2. Place 5 strips of unit breadth on the right of the square side
by side to make the length of the rectangle (x + 5) units.

3. Put 3 strips below the square to make the breadth
(x + 3) units.

4. The product (x + 5) (x + 3) should, however make the rectangle complete. Fill up the gaps with
unit squares to complete the rectangle. 15 unit squares will complete the rectangle.

Observations: The multiplication of (x + 5) (x + 3) is now represented by the rectangle.