Question

Persamaan dan Pertidaksamaan Kuadrat
menggunakan Rumus ABC
1). 4x² + 4x + 1 = 0
2). 5x (x -2) = 15
tolong bantu ya...
bsok di kumpul

Answer 1

-4 ± √(4² - 4 x 4 x 1)
1) x = ----------------------------
2 x 4
-4 ± √(16-16)
x = -----------------
8
-4
x = ------ = - 1 / 2
8

2) 5x (x-2) = 15
5x² - 10x - 15 = 0 (dibagi 5)
x² - 2x - 3 = 0

-(-2) ± √((-2)² - 4 x 1 x (-3))
x = -----------------------------------
2 x 1

2 ± √(4+12)
x = -----------------
2
2 ± √16
x = -------------
2
2 ± 4
x = ---------
2
2 + 4 6
x1 = --------- = ----- = 3
2 2
2 - 4 -2
x2 = --------- = ----- = -1
2 2