Page 1 of 3
Grade : BE8 Section: A, B ,C
Teacher : Zeinab Zeineddine
Date : 23 May 2013
Abed Al – Karim Al – Khalil Public School
Final exam : In Mathematics
Note: 20
correction
Nb Answers Note
I. 1) 64 = 26
𝑎𝑛𝑑 48 = 2⁴ × 3 then their GCD is : 2⁴ 𝐁  0.5
2)
10−1+10
10
=
0.1+10
10
=
10.1
10
= 1.01 𝐁  0.25
3) 𝑥² + (𝑥 + 4)2
≤ 2(𝑥 + 1)(𝑥 + 2) + 38
𝑥2
+ 𝑥2
+ 8𝑥 + 16 ≤ 2(𝑥2
+ 2𝑥 + 𝑥 + 2) + 38
2𝑥² + 8𝑥 + 16 ≤ 2𝑥² + 6𝑥 + 4 + 38
2𝑥² + 8𝑥 − 2𝑥² − 6𝑥 ≤ 42 − 16
2𝑥 ≤ 26
 𝑥 ≤ 13
𝑇ℎ𝑒𝑛 𝑡ℎ𝑒 𝑝𝑟𝑖𝑚𝑒 𝑛𝑢𝑚𝑏𝑒𝑟𝑠 𝑡ℎ𝑎𝑡 𝑎𝑟𝑒 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛𝑠 𝑜𝑓 𝑡ℎ𝑖𝑠 𝑖𝑛𝑒𝑞𝑢𝑎𝑙𝑖𝑡𝑦 𝑎𝑟𝑒 𝑡ℎ𝑒 𝑝𝑜𝑠𝑖𝑡𝑖𝑣𝑒𝑠 𝑝𝑟𝑖𝑚𝑒
𝑛𝑢𝑚𝑏𝑒𝑟𝑠 ≤ 13 which are: 2;5;7;11 and 13 𝐀 
1
4) (
1
13
)
359
× (−13)³⁶²=13−359
× 13362
= 13³ 𝑪 
0.25
II. 1) 𝐴 =
3
5
−
1
5
× (
5
2
+ 2) =
3
5
−
1
5
× (
5+4
2
) =
3
5
−
9
10
=
6−9
10
=
−3
10
0.75
2) 𝐵 =
3×10³×1.2×10⁻²
15×10³
=
1.2×10⁻²
5
= 0.24 × 10−2
= 2.4 × 10⁻³ 0.75
3) 𝐶 = √63 − 2√28 + √700 = 3√7 − 4√7 + 10√7 = 9√7 ≈ 23.812 0.75
4) 𝐷 = (2 − √5)
2
+ 2(8 + √20) = 4 − 4√5 + 5 + 16 + 4√5 = 25  0.75
III. 1) (E, S, M) inv prop (4,5,6) and E+S+M=111
𝐸
1
4
=
𝑆
1
5
=
𝑀
1
6
=
𝑆+𝑀+𝐸
1
4
+
1
5
+
1
6
=
111
15+12+10
60
=
111
37
60
= 111 ×
60
37
= 180
4𝐸 = 180 𝐸 = 180 ÷ 4 = 45
5𝑆 = 180 𝑆 = 36
6𝑀 = 180 𝑀 = 30
1.25
2) 30 students 100%
? 60%
Nb of girls=
60×30
100
= 18 𝑔𝑖𝑟𝑙𝑠
Nb of boys= 30-18=12 boys
0.75
IV. 1) L(3;3); C(-2;3) and
S(-2;-1)
0.5
Page 2 of 3
2) a. 𝑥𝐼 =
𝑥 𝑆+𝑥 𝐿
2
=
−2+3
2
=
1
2
and 𝑦𝐼 =
𝑦 𝑆+𝑦 𝐿
2
=
−1+3
2
= 1 0.5
b. A is the symmetric of C with respect to I  I  [AC]
𝑥𝐼 =
𝑥 𝐶+𝑥 𝐴
2

1
2
=
−2+𝑥 𝐴
2
 𝑥 𝐴 = 1 + 2 = 3
𝑦𝐼 =
𝑦 𝐶+𝑦 𝐴
2
1 =
3+𝑦 𝐴
2
 𝑦𝐴 = 2 − 3 = −1
0.5
c. ASCL is a rectangle: the diagonal bisect each other at I and 𝐴𝑆̂ 𝐶 = 90°
𝑃 = 2(𝐿 + 𝑊) = 2(4 + 5) = 18 𝑐𝑚
0.5
3) The image of CSA by vector 𝐶𝐿⃗⃗⃗⃗ is the triangle LAA’ and its right at A ( by translation)
𝐴 =
𝐴𝐿×𝐴𝐴′
2
=
4×5
2
= 10 𝑐𝑚²
0.5
V. 1) 𝑔(𝑥) = (4𝑥 + 1)² − 2(4𝑥 + 1)(𝑥 + 3) =16𝑥2
+ 8𝑥 + 1 − 2(4𝑥2
+ 12𝑥 + 𝑥 + 3)
= 16𝑥2
+ 8𝑥 + 1 − 8𝑥2
− 26𝑥 − 6
= 8𝑥² − 18𝑥 − 5
0.5
2) 𝑓(𝑥) = [(3𝑥 − 4) − (𝑥 + 5)][(3𝑥 − 4) + (𝑥 + 5)] = (2𝑥 − 9)(4𝑥 + 1)
𝑔(𝑥) = (4𝑥 + 1)[(4𝑥 + 1) − 2(𝑥 + 3)] = (4𝑥 + 1)(2𝑥 − 5)
1
3) 𝑓(𝑥) = 0(2𝑥 − 9)(4𝑥 + 1) = 0 𝑥 =
9
2
𝑜𝑟 𝑥 =
−1
4
0.5
4) a. 𝐴(𝑥) =
𝑓(𝑥)
𝑔(𝑥)
=
(2𝑥−9)(4𝑥+1)
(4𝑥+1)(2𝑥−5)
(4𝑥 + 1)(2𝑥 − 5)≠ 0 𝑥 ≠
−1
4
𝑎𝑛𝑑 𝑥 ≠
5
2
0.5
b. 𝐴(𝑥) =
(2𝑥−9)(4𝑥+1)
(4𝑥+1)(2𝑥−5)
=
2𝑥−9
2𝑥−5
=
2
3
3(2𝑥 − 9) = 2(2𝑥 − 5)
6𝑥 − 27 = 4𝑥 − 10
2𝑥 = 17 𝑥 =
17
2
0.5
VI.
𝐹𝑟𝑒𝑞 =
𝐴𝑛𝑔𝑙𝑒×𝑇
360°
%𝑅𝐹 =
𝐹𝑟𝑒𝑞
𝑇
× 100
Total=200 persons
1) Blue=(36° × 200) ÷ 360 = 20 𝑝𝑒𝑟𝑠𝑜𝑛𝑠
Black= 60 persons ; Green= 50 persons ; Brown= 70 persons
Colors Freq %RF
Black 60 30%
Brown 70 35%
Blue 20 10%
Green 50 25%
Total 200 100%
1.5
Page 3 of 3
2)
0.5
VII. C(0; 3cm) ; BC= 3 cm ; N [AC].
1) OC=OB= R= 3 cm and CB= 3 cm (given) then OCB is an equilateral ∆ 0.5
2) 𝐴𝐶̂ 𝐵 = 90° ( opposite to the diameter) and 𝐴𝐵̂ 𝐶 = 60° (equilateral ∆)
𝑡ℎ𝑒𝑛 𝐶𝐴̂ 𝐵 = 30° .
𝐴𝐵𝐶 𝑖𝑠 𝑎 𝑠𝑒𝑚𝑖 − 𝑒𝑞𝑢𝑖𝑙𝑎𝑡𝑒𝑟𝑎𝑙 ∆
1
3) AC=
𝐵𝐶√3
2
=
6√3
2
= 3√3 (𝑜𝑝𝑝𝑜𝑠𝑖𝑡𝑒 𝑡𝑜 𝑡ℎ𝑒 𝑎𝑛𝑔𝑙𝑒 60°)
In the ∆ ACB:
O[AB] By the midpoint th. ON=
𝐵𝐶
2
= 1.5 𝑐𝑚 and (ON) // (BC)
N [AC]
1
4) In the triangle AMB we have:
𝐵̂ = 90° 𝑎𝑛𝑑 𝑀𝐴̂ 𝐵 = 30° then AMB is a semi equilateral ∆
𝐴𝐵 =
𝐴𝑀√3
2
 6=
𝐴𝑀√3
2
 𝐴𝑀 =
12
√3
= 4√3
BM=
𝐴𝑀
2
= 2√3
1
5) 𝐴 𝐶𝑂𝐵 =
𝜋𝑅²×𝐶𝑂̂ 𝐵
360°
=
𝜋×9×60
360
=
3𝜋
2
𝑐𝑚² 1
6) 𝐴𝑁̂ 𝑂 = 𝐴𝐶̂ 𝐵 = 90° ( corresponding angles)
𝐴 𝑎𝑛𝑑 𝑂 𝑎𝑟𝑒 𝑓𝑖𝑥𝑒𝑑 𝑝𝑜𝑖𝑛𝑡𝑠 𝑡ℎ𝑒𝑛 𝑁 𝑏𝑒𝑙𝑜𝑛𝑔𝑠 𝑡𝑜 𝑎 𝑐𝑖𝑟𝑐𝑙𝑒 𝑜𝑓 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 [𝐴𝑂]
1
60
70
20
50
0
10
20
30
40
50
60
70
80
Black Brown Blue Green
Bar graph
Freq

Final exam g8 correction

  • 1.
    Page 1 of3 Grade : BE8 Section: A, B ,C Teacher : Zeinab Zeineddine Date : 23 May 2013 Abed Al – Karim Al – Khalil Public School Final exam : In Mathematics Note: 20 correction Nb Answers Note I. 1) 64 = 26 𝑎𝑛𝑑 48 = 2⁴ × 3 then their GCD is : 2⁴ 𝐁  0.5 2) 10−1+10 10 = 0.1+10 10 = 10.1 10 = 1.01 𝐁  0.25 3) 𝑥² + (𝑥 + 4)2 ≤ 2(𝑥 + 1)(𝑥 + 2) + 38 𝑥2 + 𝑥2 + 8𝑥 + 16 ≤ 2(𝑥2 + 2𝑥 + 𝑥 + 2) + 38 2𝑥² + 8𝑥 + 16 ≤ 2𝑥² + 6𝑥 + 4 + 38 2𝑥² + 8𝑥 − 2𝑥² − 6𝑥 ≤ 42 − 16 2𝑥 ≤ 26  𝑥 ≤ 13 𝑇ℎ𝑒𝑛 𝑡ℎ𝑒 𝑝𝑟𝑖𝑚𝑒 𝑛𝑢𝑚𝑏𝑒𝑟𝑠 𝑡ℎ𝑎𝑡 𝑎𝑟𝑒 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛𝑠 𝑜𝑓 𝑡ℎ𝑖𝑠 𝑖𝑛𝑒𝑞𝑢𝑎𝑙𝑖𝑡𝑦 𝑎𝑟𝑒 𝑡ℎ𝑒 𝑝𝑜𝑠𝑖𝑡𝑖𝑣𝑒𝑠 𝑝𝑟𝑖𝑚𝑒 𝑛𝑢𝑚𝑏𝑒𝑟𝑠 ≤ 13 which are: 2;5;7;11 and 13 𝐀  1 4) ( 1 13 ) 359 × (−13)³⁶²=13−359 × 13362 = 13³ 𝑪  0.25 II. 1) 𝐴 = 3 5 − 1 5 × ( 5 2 + 2) = 3 5 − 1 5 × ( 5+4 2 ) = 3 5 − 9 10 = 6−9 10 = −3 10 0.75 2) 𝐵 = 3×10³×1.2×10⁻² 15×10³ = 1.2×10⁻² 5 = 0.24 × 10−2 = 2.4 × 10⁻³ 0.75 3) 𝐶 = √63 − 2√28 + √700 = 3√7 − 4√7 + 10√7 = 9√7 ≈ 23.812 0.75 4) 𝐷 = (2 − √5) 2 + 2(8 + √20) = 4 − 4√5 + 5 + 16 + 4√5 = 25  0.75 III. 1) (E, S, M) inv prop (4,5,6) and E+S+M=111 𝐸 1 4 = 𝑆 1 5 = 𝑀 1 6 = 𝑆+𝑀+𝐸 1 4 + 1 5 + 1 6 = 111 15+12+10 60 = 111 37 60 = 111 × 60 37 = 180 4𝐸 = 180 𝐸 = 180 ÷ 4 = 45 5𝑆 = 180 𝑆 = 36 6𝑀 = 180 𝑀 = 30 1.25 2) 30 students 100% ? 60% Nb of girls= 60×30 100 = 18 𝑔𝑖𝑟𝑙𝑠 Nb of boys= 30-18=12 boys 0.75 IV. 1) L(3;3); C(-2;3) and S(-2;-1) 0.5
  • 2.
    Page 2 of3 2) a. 𝑥𝐼 = 𝑥 𝑆+𝑥 𝐿 2 = −2+3 2 = 1 2 and 𝑦𝐼 = 𝑦 𝑆+𝑦 𝐿 2 = −1+3 2 = 1 0.5 b. A is the symmetric of C with respect to I  I  [AC] 𝑥𝐼 = 𝑥 𝐶+𝑥 𝐴 2  1 2 = −2+𝑥 𝐴 2  𝑥 𝐴 = 1 + 2 = 3 𝑦𝐼 = 𝑦 𝐶+𝑦 𝐴 2 1 = 3+𝑦 𝐴 2  𝑦𝐴 = 2 − 3 = −1 0.5 c. ASCL is a rectangle: the diagonal bisect each other at I and 𝐴𝑆̂ 𝐶 = 90° 𝑃 = 2(𝐿 + 𝑊) = 2(4 + 5) = 18 𝑐𝑚 0.5 3) The image of CSA by vector 𝐶𝐿⃗⃗⃗⃗ is the triangle LAA’ and its right at A ( by translation) 𝐴 = 𝐴𝐿×𝐴𝐴′ 2 = 4×5 2 = 10 𝑐𝑚² 0.5 V. 1) 𝑔(𝑥) = (4𝑥 + 1)² − 2(4𝑥 + 1)(𝑥 + 3) =16𝑥2 + 8𝑥 + 1 − 2(4𝑥2 + 12𝑥 + 𝑥 + 3) = 16𝑥2 + 8𝑥 + 1 − 8𝑥2 − 26𝑥 − 6 = 8𝑥² − 18𝑥 − 5 0.5 2) 𝑓(𝑥) = [(3𝑥 − 4) − (𝑥 + 5)][(3𝑥 − 4) + (𝑥 + 5)] = (2𝑥 − 9)(4𝑥 + 1) 𝑔(𝑥) = (4𝑥 + 1)[(4𝑥 + 1) − 2(𝑥 + 3)] = (4𝑥 + 1)(2𝑥 − 5) 1 3) 𝑓(𝑥) = 0(2𝑥 − 9)(4𝑥 + 1) = 0 𝑥 = 9 2 𝑜𝑟 𝑥 = −1 4 0.5 4) a. 𝐴(𝑥) = 𝑓(𝑥) 𝑔(𝑥) = (2𝑥−9)(4𝑥+1) (4𝑥+1)(2𝑥−5) (4𝑥 + 1)(2𝑥 − 5)≠ 0 𝑥 ≠ −1 4 𝑎𝑛𝑑 𝑥 ≠ 5 2 0.5 b. 𝐴(𝑥) = (2𝑥−9)(4𝑥+1) (4𝑥+1)(2𝑥−5) = 2𝑥−9 2𝑥−5 = 2 3 3(2𝑥 − 9) = 2(2𝑥 − 5) 6𝑥 − 27 = 4𝑥 − 10 2𝑥 = 17 𝑥 = 17 2 0.5 VI. 𝐹𝑟𝑒𝑞 = 𝐴𝑛𝑔𝑙𝑒×𝑇 360° %𝑅𝐹 = 𝐹𝑟𝑒𝑞 𝑇 × 100 Total=200 persons 1) Blue=(36° × 200) ÷ 360 = 20 𝑝𝑒𝑟𝑠𝑜𝑛𝑠 Black= 60 persons ; Green= 50 persons ; Brown= 70 persons Colors Freq %RF Black 60 30% Brown 70 35% Blue 20 10% Green 50 25% Total 200 100% 1.5
  • 3.
    Page 3 of3 2) 0.5 VII. C(0; 3cm) ; BC= 3 cm ; N [AC]. 1) OC=OB= R= 3 cm and CB= 3 cm (given) then OCB is an equilateral ∆ 0.5 2) 𝐴𝐶̂ 𝐵 = 90° ( opposite to the diameter) and 𝐴𝐵̂ 𝐶 = 60° (equilateral ∆) 𝑡ℎ𝑒𝑛 𝐶𝐴̂ 𝐵 = 30° . 𝐴𝐵𝐶 𝑖𝑠 𝑎 𝑠𝑒𝑚𝑖 − 𝑒𝑞𝑢𝑖𝑙𝑎𝑡𝑒𝑟𝑎𝑙 ∆ 1 3) AC= 𝐵𝐶√3 2 = 6√3 2 = 3√3 (𝑜𝑝𝑝𝑜𝑠𝑖𝑡𝑒 𝑡𝑜 𝑡ℎ𝑒 𝑎𝑛𝑔𝑙𝑒 60°) In the ∆ ACB: O[AB] By the midpoint th. ON= 𝐵𝐶 2 = 1.5 𝑐𝑚 and (ON) // (BC) N [AC] 1 4) In the triangle AMB we have: 𝐵̂ = 90° 𝑎𝑛𝑑 𝑀𝐴̂ 𝐵 = 30° then AMB is a semi equilateral ∆ 𝐴𝐵 = 𝐴𝑀√3 2  6= 𝐴𝑀√3 2  𝐴𝑀 = 12 √3 = 4√3 BM= 𝐴𝑀 2 = 2√3 1 5) 𝐴 𝐶𝑂𝐵 = 𝜋𝑅²×𝐶𝑂̂ 𝐵 360° = 𝜋×9×60 360 = 3𝜋 2 𝑐𝑚² 1 6) 𝐴𝑁̂ 𝑂 = 𝐴𝐶̂ 𝐵 = 90° ( corresponding angles) 𝐴 𝑎𝑛𝑑 𝑂 𝑎𝑟𝑒 𝑓𝑖𝑥𝑒𝑑 𝑝𝑜𝑖𝑛𝑡𝑠 𝑡ℎ𝑒𝑛 𝑁 𝑏𝑒𝑙𝑜𝑛𝑔𝑠 𝑡𝑜 𝑎 𝑐𝑖𝑟𝑐𝑙𝑒 𝑜𝑓 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 [𝐴𝑂] 1 60 70 20 50 0 10 20 30 40 50 60 70 80 Black Brown Blue Green Bar graph Freq