Soal Matematika Persamaan Kuadrat Kelas 9 (3 SMP) DOCX

Title	Soal Matematika Persamaan Kuadrat Kelas 9 (3 SMP)
Author	Nurhadi Nurhadi
Pages	16
File Size	75 KB
File Type	DOCX
Total Downloads	496
Total Views	937

Summary

Description

Pilihan Ganda (25 Soal) 1. Tentukan x2 – 8x + 15 = 0 a. -3, dan -5 c. 3, dan 5 b. -3, dan 5 d. 3, dan -5 Pembahasan Syarat: a = 1, b = -8, c = 15 p.q = c dan p + q = b p.q = 15 dan p + q = -8 p q p.q p + q -3 -5 15 -8 x2 – 8x + 15 = 0 (x – 3)(x – 5) = 0 x1 = 3 dan x2 = 5 Jawaban: C (3, dan 5) 2. 2x2 + 3x – 2 = 0 a. 2, dan -1/2 c. -2, dan -1/2 b. -2, dan ½ d. 2, dan 1/2 Pembahasan 2x2 + 3x – 2 = 0 a = 2, b= 3, c= -2 (x + p)2 + q = 0 ax2 + bx + c = 0 p = b 2a = 3 2.2 = 3 4 q = c a ( b 2a ) 2 = 2 2 ( 3 2.2) 2 =¿ 1 9 16 = 16 16 9 16 = 25 16 (x + 3 4 )2 + ( 25 16 ) = 0 (x + 3 4 )2 = ( 25 16 ) x + 3 4 = ± 25 16 x = ± 25 16 - 3 4 = ± 5 4 - 3 4 x1 = - 5 4 - 3 4 = - 8 4 x1 = -2 x2 = 5 4 - 3 4 = 2 4 = 1 2 1...