Soal dan Jawaban Sistem pertidaksamaan (Pertemuan ke-4)
SOAL 2. 5 > 4x – 1 4. 3x – 4 ≥ NIM X + 1 6. 2x 2 + 11x + 3 ≤ -2 8. 3(x – 2) ≥ x + 1 10. 2x + 6/ x -2 ≤ x + 1 JAWAB 2. 5 > 4x - 1 4x > -1 -5 4x > -6 x > 6/4 x > 3/2 4. 3x - 4 ≥ 8x + 1 3x - 8x ≥ 1 + 4 -5x ≥ 5 x ≥ 5/5 x ≥ 1 6. 2x 2 + 11x + 3 ≤ -2 2x 2 + 11x + 3 + 2 ≤ 0 2x 2 + 11x + 5 ≤ 0 (x + 5) (2x + 1) ≤ 0 X = -5, x = -1/2 -5 ≤ x ≤ -1/2 8. 3(x – 2) ≥ x + 1 3x – 6 ≥ x + 1 3x – x ≥ 1 + 6 2x ≥ 7 X ≥ 7/2 10. 2x + 6/ x -2 ≤ x + 1 2x + 6 ≤ (x +1) (x – 2) 2x + 6 ≤ x 2 – 2x + x -2 2x + 6 ≤ x 2 – x -2 2x + 6 –x 2 + x + 2 ≤ 0 -x 2 + 3x + 8 ≤ 0 X 2 - 3x -8 ≥ 0 Menggunakan rumus abc X1,2 = -b ± √ b 2 – 4ac/ 2a = - (-3) ± √ (-3) 2 -4 (1) (-8) = 3 ± √ 9 + 32/ 2 = 3 ± √ 41/2 X1 = 3 - √ 41/2 X2 = 3 + √ 41/2