Jawaban:

betul

Penjelasan:

1) -7x + 6y - 2y - 3x

= -7x - 3x + 6y - 2y

= (-7-3)x + (6-2) y

= -10x + 4y ---> A

2) 5(3x-1) - 12x + 9

= 15x - 5 - 12x + 9

= 15x - 12x -5 + 9

= 3x + 4 ---> C

3) 5x² - 2xy - 8y² - 6x² - xy + 3y²

= 5x² - 6x² - 2xy - xy - 8y² + 3y²

= -x² - 3xy - 5y² ---> B

4) 4x (-3x + 2y)

= -12x² + 8 xy ---> B

5) Diketahui m= -2 ; n= 5

m² + 3mn

= (-2)² + 3(-2)(5)

= 4 - 30 = -26 ---> D

6)

\frac{3x}{2} \div \frac{ {6x}^{2} }{4} = \frac{3x}{2} \times \frac{4}{ {6x}^{2} } = \frac{2}{2x} = \frac{1}{x}

2

3x

÷

4

6x

2

=

2

3x

×

6x

2

4

=

2x

2

=

x

1

---> C

7)

\frac{ {3y}^{3} \times {4y}^{4} }{ {6y}^{5} } = \frac{ {12y}^{7} }{ {6y}^{5} } = {2y}^{2}

6y

5

3y

3

×4y

4

=

6y

5

12y

7

=2y

2

---> B

8) (2x - 2) (x + 5)

= 2x.x + 5.2x + (-2).x + (-2).5

= 2x² + 10x - 2x - 10

= 2x² + 8x - 10 ---> C

9)misal robot = x ; mobil-mobilan = y

Arman mempunyai = 5x + 8y

diberi ibu = 2x

yang diberikan ke Arif = 3y

maka kalimatnya menjadi =

5x + 8y + 2x - 3y

= 5x + 2x + 8y - 3y = 7x + 5y ---> C

10) (10 - x)² - (8 - x)² = 28 m²

100 - 20x + x² -(64 - 16x + x²) = 28 m²

100 - 20x + x² - 64 + 16 x - x² = 28 m²

100 - 64 - 20x + 16x + x² - x² = 28 m²

36 - 4x = 28

36 - 28 = 4x

8 = 4x

x = 2

maka luas tanah pak Tohir yang sebenarnya

(10-x)² = 100 - 20x + x²

= 100 - 20.2 + 2²

= 100 - 40 + 4

= 64 m²---> C