Jabarkan.
1. x2 + (x + 5) (x + 1).
2. (a + 4)2 – (a – 2) (a + 2)
3. (+2) (y – 7) – y (y – 4)
4. 2(x – 1)2 – (2x – 1)2.
Pembahasan
Jawaban soal 1.
x2 + (x + 5) (x + 1)
x2 + x2 + x + 5x + 5
2x2 + 6x + 5
Jadi x2 + (x + 5) (x + 1) = 2x2 + 6x + 5.
Jawaban soal 2.
(a + 4)2 – (a – 2) (a + 2)
(a2 + 8a + 16) – (a2 – 4)
a2 + 8a + 16 – a2 + 4
8a + 20
Jadi (a + 4)2 – (a – 2) (a + 2) = 8a + 20.
Jawaban soal 3.
(+2) (y – 7) – y(y – 4).
(2y – 14) – (y2 – 4y)
2y – 14 – y2 + 4y
-y2 + 6y – 14.
Jadi (+2) (y – 7) – y(y – 4) = -y2 + 6y – 14.
Jawaban soal 4.
2(x – 1)2 – (2x – 1)2.
2(x2 – 2x + 1) – (4x2 – 4x + 1)
2x2 – 4x + 2 – 4x2 + 4x – 1
-2x2 + 1.
Jadi, 2(x – 1)2 – (2x -1)2 = -2x2 + 1.