Kak tolong dijawab ​

1. = 4(9a – 7b – 5) – (21a + 12b + 43)

= 36a – 28b – 20 – 21a – 12b – 43

= 15a – 40b – 63

2. = 9x² – 12x + 36 – 7x² + 24x – 48

= 9x² – 7x² – 12x + 24x + 36 – 48

= 2x² + 12x – 12

= 13a² – 9b – 12 + 9a² + 12b + 24

= 13a² + 9a² – 9b + 12b – 12 + 24

= 22a² + 3b + 12

kata "dari" dalam pengurangan berarti bilangan kedua dikurangi bilangan pertama (dibalik)

= (19x – 17y) – (3x + 5y)

= 19x – 17y – 3x – 5y

= 16x – 22y

1. = 7a(2a – 3b – 5c)

= 14a – 21b – 35c

2. = (2x + 4)(2x + 4)

= 4x² + 8x + 8x + 16

= 4x² + 16x + 16

3. = (2x + 4)(2x – 4)

= 4x² – 8x + 8x – 16

= 4x² – 16

4. = (2x – 4)(2x – 4)

= 4x² – 8x – 8x + 16

= 4x² – 16x + 16