Mohon dijawab cara penyelesaianya dan penjelasanyadibutuhkan segera thanks
4. m – n = 3
5. f(x) = f(x) = -1/2 x² – 4x – 8
Penjelasan dengan langkah-langkah:
4. a = 1, b = -13, c = 8
m + n = -b/a = -(-13)/1 = 13
m x n = c/a = 8/1 = 8
m² – n² = 39
(m – n)(m + n) = 39
(m – n) x 13 = 39
(m – n) = 39/13 = 3
5. lewat (-6, -2). puncak (-4,0), titik lain (-2,-2)
• persamaan umum f(x) = ax² + bx + c
• membuat persamaan
– lewat (-6, -2)
a(-6)² + b(-6) + c = -2
36a – 6b + c = -2
– lewat (-4, 0)
a(-4)² + b(-4) + c = 0
16x² – 4b + c = 0
– lewat (-2, -2)
a(-2)² + b(-2) + c = -2
4a – 2b + c = -2
• mencari a, b, c
36a – 6b + c = -2
16x² – 4b + c = 0
————————- –
20a – 2b = -2
10a – b = -1
16x² – 4b + c = 0
4a – 2a + c = -2
———————— –
12a – 2b = 2
6a – b = 1
10a – b = -1
6a – b = 1
—————- –
4a = -2
a = -1/2
6a – b = 1
6.(-1/2) – b = 1
-3 – b = 1
– b = 1 + 3
-b = 4
b = -4
4a – 2b + c = -2
4.(-1/2) – 2.(-4) + c = -2
-2 + 8 + c = -2
6 + c = -2
c = -2 – 6 = -8
maka a = -1/2, b = -6, c = -8
persamaannya
y = -1/2 x² – 4x – 8
f(x) = -1/2 x² – 4x – 8