Question

Tolong no 2 yang ditanya:nilai p
dan no 3 yang ditanya:nilai b

Answer 1

2.
misal c = 8√5 / 5
a.b = 4 - 4p
|b| = √(20+p²)

|c| = a.b/ |b|
8√5/5 = (4-4p)/ √(20+p²)
kuadratkan kedua ruas
|c|² = (a.b)² / |b|²

64/5 = (4-4p)²/ (20+p²)
5(4-4p)² = 64 (20 + p²)
5(16-32p+16p²) = 1280 + 64 p²
80 - 160 p + 80 p² = 1.280 + 64p²
80p²- 64 p² -160 p +80 - 1280 = 0
16 p² -160p - 1200 = 0 sederhanakan di :16
p² - 10p  - 75 = 0
(p - 15)(p+5) = 0
p = 15 atau p = - 5