Example If x = 4 and y = 3 find the value of

Example If a = 2, b = 3, c = 2 evaluate 2 a + 3 b + 4 c.

Solution: 2 a + 3 b + 4 c = 2 ( 2 ) + 3 ( 3 ) + 4 ( 2 )

                                       = 4 + 9 + 8

                                      = 21

Example Evaluate 2 a² + 5 b + 7 if a = 2, and b = 1

Solution: 2 a² + 5 b + 7 = 2 ( 2 )² + 5 ( 1 ) + 7

                                      = 2 ( 4 ) + 5 + 7

                                      = 8 + 12

                                      = 20

Example Tom and Jackson walk at a rate of x and y km / hr respectively. If they start from the same spot and go in the same direction, what is the distance between them after t hours ( y > x ). Calculate the distance if x = 3, y = 4 and t = 2.

Solution: In ‘ t ’ hours Tom will reach the distance of xt km (\ distance = speed ´ time ). In ‘ t ’ hours Jackson will reach the distance of y t km. Since y > x and t > 0 we have y t > x t . \ y t - x t = distance between Tom and Jackson after ‘ t ’ hours. ( Note that they walk in the same direction Þ both x and y are positive ).

Taking x = 3, y = 4 and t = 2 in y t - x t we get, (4) (2) - (3) (2) = 8 - 6 = 2 km.

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Index

3.1 - Introduction
3.2 - Monomial, Polynomials
3.3 - H.C.F and L.C.M

Chapter 4