mohon di jawab ya kak soalnya besok dikumpul

1) ( 3x - 4y )( 9x² + 12xy + 8y² )
= 27x³ - 36x²y + 36x²y - 48xy² + 24xy² - 32y³
= 27x³ - 24xy² - 32y³

2) x² + 7x
-------------------
x² + 3x - 28

= x ( x + 7 )
----------------------
( x - 4)( x + 7 )

= x
-----------
x - 4

3) f(x) = 3x + 2
a) f(5) = 3(5) + 2 = 15 + 2 = 17
b) f(a) = 3a + 2
38 = 3a + 2
38 - 2 = 3a
36 = 3a
a = 36 ÷ 3
a = 12

4) a) g(x) = px + q
g(3) = 3p + q = - 4
g(-2) = - 2p + q = 1
---------------------------(-)
5p = - 5
p = - 1
subtitusi
3p + q = - 4
3p - 1 = - 4
3p = - 4 + 1
3p = - 3
p = - 1
b) g(x) = px + q
g(x) = - x - 1
c) g(-5) = - (-5) - 1 = 5 - 1 = 4

5) m = ( y2 - y1 ) / ( x2 - x1 )
m = ( 4 + 2 ) / ( - 2 - 5 )
m = 6 / - 7
m = - 6/7

6) a) 3x + 2y - 6 = 0
2y = - 3x + 6
m = -3/2
gradien sejajar
m1 = m2 = - 3/2
pers garis
y - y1 = m ( x - x1 )
y + 4 = - 3/2 ( x - 8 )
y = - 3/2 x + 12 - 4
y = - 3/2 x + 8 ( dikali 2)
2y = - 3x + 16
2y + 3x = 16
b) 2x - 4y + 8 = 0
- 4y = - 2x - 8
m = - 2/-4
m = ½
gradien tegak lurus
m1 . m2 = - 1
½ . m2 = - 1
m2 = -1 ÷ ½
m2 = - 2
Pers garis
y - y1 = m ( x - x1 )
y + 4 = - 2 ( x - 8)
y = - 2x + 16 - 4
y + 2x = 12

7) 2x + y = 4
2x - 3y = 12
-------------------(-)
4y = - 8
y = - 2
subtitusi
2x + y = 4
2x - 2 = 4
2x = 4 + 2
2x = 6
x = 3
nilai 4x - y
= 4(3) - (-2)
= 12 + 2
= 14

8) misal
bilangan 1 = x
bilangan 2 = y
x + y = 35
x - y = 5
---------------(-)
2y = 30
y = 15
subtitusi
x - y = 5
x - 15 = 5
x = 5 + 15
x = 20
nilai x • y
= 20 • 15
= 300

9) ½d1 = ½ × 12 = 6 cm
½d2 = ½ × 16 = 8 cm
sisi miring = √(½d1² + ½d2²)
= √(6² + 8²)
= √(36 + 64)
= √100
= 10 cm
K = 4 × sisi miring
= 4 × 10
= 40 cm

10) c = √a² + b²
c = √(4)² + (5)²
c = √16 + 25
c = √41
c tdk sm sg 6 berarti segitiga sembarang

c = √(6)² + (8)²
c = √36 + 64
c = √100
c = 10
c sama² 10 cm, berarti segitiga siku²

c = √(6² + 8²)
c = √(36 + 64)
c = √100
c = 10
c tdk sama dg 10, berarti segitiga sembarang