F.2 Maths

69. 3 ( x － 2 ) ＞ 2 ( x － 3 )

Sol:

3 ( x － 2 ) ＞ 2 ( x － 3 )

6x － 6 ＞ 2x － 6

4x ＞ 0

x ＞ 0

Ans: x ＞ 0

71. The product of 3 and x is less than 12. If x is an integer, find the

greatest value of x.

Sol:

3x ＜ 12

x ＜ 4

x is an integer, so greatest value of x is 3

Ans: 3

72. If the sum of three consecutive odd integer is greater than 89. Find

the least value of the smallest number.

Sol:

Suppose x, x ＋ 2, x ＋ 4 are three consecutive odd integer

x ＋ ( x ＋ 2 ) ＋ ( x ＋ 4 ) ＞ 89

3x ＋ 6 ＞ 89

3x ＞ 83

x ＞ 83/3

x is an odd integer, so the smallest number of x is 29

Ans: 29

69. x > 0

71. x = 3

72. x = 29