Question

Pliss tolong gue caranya nyelesain soal MTK​

Answer 1

persamaan parabola y=ax² + bx + c

melalui titik (0,−8)

−8 = a(0)² + b(0) + c

c = −8 .....................................(1)

melalui titik (4, 0)

a(4)² + b(4) −8 = 0

16a + 4b − 8 = 0......................(2)

melalui titik (−1, 0)

a(−1)² + b(−1) − 8 = 0

a − b − 8 = 0 ............................(3)

b =( a − 8), subtitusikan ke persamaan (3)

16a + 4b −8 = 0

16a + 4(a − 8) − 8 = 0

16a + 4a − 32 − 8 = 0

20a = 40

a = 2, subtitusikan kepersamaan (3)

a − b − 8 = 0

2 − b − 8 = 0

b = −6 ......................................(4)

jadi a = 2, b = −6, c = −8

ax² + bx + c