(The first part) The answers to the exercises p 152 to P 153 in the mathematics guidance of the first grade.
1.C 2。 C 3。 D 4。 A 5。 A six. C 7。 A
8.4.5 6.5
9.40
10.6 and 14
1 1.( 1)9 (2) 15
12.AB= 1 BC= 1.5 CD=2
13.( 1)7(2) 1/2 * M(3) 1/2(BC-AC)
14.6 10 n(n- 1)/2