Selesaikanlah.
1. 2x2 = 14.
2. 4x2 – 15 = 0.
3. (x + 6)2 = 2.
4. (x – 1)2 = 49.
Pembahasan
Jawaban soal 1.
2x2 = 14
x2 = 14 : 2
x2 = 7
x = ± √7.
Jawab: x = √7, x = – √7.
Jawaban soal 2.
4x2 – 15 = 0
4x2 = 15
x2 = 15/4
x = ± √15/4 = ± 1/2 √15.
Jawab: x = 1/2√15, x = – 1/2 √15.
Jawaban soal 3.
(x + 6)2 = 2.
x + 6 = ± √2.
x = -6 ± √2.
Jawab: x = -6 + √2, x = -6 – √2.
Jawaban soal 4.
(x – 1)2 = 49.
x – 1 = ± √49
x – 1 = ±7
x = 1 ± 7
x = 1 + 7 = 8.
x = 1 – 7 = -6.
Jawab: x = 8, x = -6.