cara memfaktorkan, melengkapkan kuadrat sempurna, dan dengan rumus. a. 5x²+6x-20=0 b. x²-2x-2=0 c. x²+x-3=0

satu² aja dik..... saya yg a) dg melengkapkan kuadrat
5x² + 6x = 20
x² + (6/5)x = 4
x² + (6/5)x + (6/10)² = 4 + (6/10)²
x² + (6/5)x + (3/5)² = 4 + (3/5)²
(x + 3/5)² = 109/25
x + 3/5 = ±√(109/25)
x = -3/5 ± (1/5)√109
eh trnyata faktor yg ditanya... gpp langsung aja faktorkan
(x - ((-3/5) + (1/5)√109))(x - ((-3/5) - (1/5)√109))
= (x + (3/5) - (1/5)√109)(x + (3/5) + (1/5)√109)
= (1/5)(5x + 3 - √109)(1/5)(5x + 3 + √109)
= (1/25)(5x + 3 - √109)(5x + 3 + √109)