no. 1 = 6
no. 2 = 7
no. 3 = 8
no. 4 = 9
no.5 = 10
Ini yang tulisan tangan, yang aku kerjain. Moga kebaca..
Saya kerjakan semua saja karena poinnya besar!
Nomor 6
a. (x + 2)(x + 4)
= x² + 4x + 2x + 8
= x² + 6x + 8
b. (2p + 5)(2p – 5)
Dari rumus (a + b)(a – b) = a² – b²
dengan a = 2p dan b = 5, maka
(2p + 5)(2p – 5) = (2p)² – 5²
= 4p² – 25
c. (4 + 2m)(m – 8)
= 4m – 32 + 2m² – 16m
= 2m² – 12m – 32
d. (10x – 3)(2x – 1)
= 20x² - 10x – 6x + 3
= 20x² – 16x + 3
e. (7 – x)(7x – 1)
= 49x – 7 – 7x² + x
= -7x² + 50x – 7
Nomor 7
Soal tidak valid!
Nomor 8
Bentuk pangkat. a^p / b^q = (a/b)^(p – q)
a. 5p²q : pq = 5p
b. 2ab² : 6a²b = 1/3 a⁻¹b = b / (3a)
Untuk c, d & e pengerjaannya bukan seperti a & b !
c. (8xy² + 2x) : 4y
= [2x(4y² + 1)] / (4y)
= [x(4y² + 1)] / (2y)
d. (5m² – 5n²) : (m² – n²)
= 5(m² – n²) / (m² – n²)
= 5
e. (24ab + 6b) : (12ab² – 6a)
= [6b(4a + 1)] / [6a(2b² – 1)]
= [b(4a +1)] / [a(2b² – 1)]
Nomor 9
a. (2x + 5)³
Dengan menggunakan rumus (a + b)³ = a³ + 3a²b + 3ab² + b³
dimana a = 2x dan b = 5, maka
(2x + 5)³ = (2x)³ + 3(2x)²(5) + 3(2x)(5)² + 5³
= 8x³ + 3(4x²)(5) + 3(2x)(25) + 125
= 8x² + 60x² + 150x + 125
b. (-x + 8)²
Dengan menggunakan rumus (a + b)² = a² + 2ab + b²
(-x + 8)² = (-x)² + 2(-x)(8) + 8²
= x² – 16x + 64
c. (2x – 2y)²
Dengan menggunakan rumus (a – b)² = a² – 2ab + b²
(2x – 2y)² = (2x)² – 2(2x)(2y) + (2y)²
= 4x² – 8xy + 4y²
Nomor 10
a. (x + 4)² + (x – 4)²
= (x² + 2x.4 + 4²) + (x² – 2x.4 + 4²)
= 2x² + 32
b. (5 – y)² + (5y – 1)²
= (5² – 2.5y + y²) + [(5y)² – 2(5y).1 + 1²]
= (25 – 10y + y²) + (25y² – 10y + 1)
= 26y² – 20y + 26
c. (1/2 x + 2)² + (1/2 x – 2)²
= [(1/2 x)² + 2(1/2 x)2 + 2²] + [(1/2 x)² – 2(1/2 x)2 + 2²]
= [1/4 x² + 2x + 4] + [1/4 x² – 2x + 4]
= 1/2 x² + 8
6a. (x + 2)(x + 4)
= x² + 4x + 2x + 8
= x² + 6x + 8
b. (2p + 5)(2p – 5)
= 4p² – 10p + 10p – 25
= 4p² – 25
c. (4 + 2m)(m – 8)
= 4m – 32 + 2m² – 16m
= 2m² – 12m – 32
d. (10x – 3)(2x – 1)
= 20x² – 10x – 6x + 3
= 20x² – 16x + 3
e. (7 – x)(7x – 1)
= 49x – 7 – 7x² + x
= -7x² + 50x – 7
7. L = 1/2 × a × t
L = 1/2 × (5x + 3) × (2x – 2)
L = 1/2 × (5x + 3) × 2(x – 1)
L = (5x + 3)(x – 1)
L = 5x² – 5x + 3x – 3
L = 5x² – 2x – 3
8a. 5p²q : pq
= pq(5p)/pq
= 5p
b. 2ab² : 6a²b
= 2ab(b)/2ab(3a)
= b/(3a)
c. (8xy² + 2x) : 4y
= 2(4xy² + x)/(4y)
= (4xy² + x)/(2y)
d. (5m² – 5n²) : (m² – n²)
= 5(m² – n²)/(m² – n²)
= 5
e. (24ab + 6b) : (12ab² – 6a)
= 6(4ab + b)/6(2ab² – a)
= (4ab + b)/(2ab² – a)
9a. (2x + 5)³
= (2x)³ + 3 . (2x)² . 5 + 3 . 2x . 5² + 5³
= 8x³ + 60x² + 150x + 125
b. (-x + 8)²
= (-x)² + 2 . (-x) . 8 + 8²
= x² – 16x + 64
c. (2x – 2y)²
= (2x)² – 2 . 2x . 2y + (2y)²
= 4x² – 8xy + 4y²
10a. (x + 4)² + (x – 4)²
= (x² + 8x + 16) + (x² – 8x + 16)
= 2x² + 32
b. (5 – y)² + (5y – 1)²
= (25 – 10y + y²) + (25y² – 10y + 1)
= 26y² – 20y + 26
c. (1/2x + 2)² + (1/2x – 2)²
= (1/4x² + 2x + 4) + (1/4x² – 2x + 4)
= 1/2x² + 8