c. y = -8x2 – 16x – 1.
Jawaban: -(-16)/(2 x (-8)) = -1.
2. Tentukan nilai optimum fungsi berikut ini.
a. y = -6x2 + 24x – 19.
Baca Juga: Soal UTS IPS Kelas 9 Semester 1 Disertai Kunci Jawaban, Lengkap
Jawaban: y = -(D)/4a = -(b2 – 4ac)/4a = -(24)2 – 4(-6)(-19)/4(-6) = -(576 – 456)/-24 = 5.
b. y = 2/5x2 – 3x + 15.
Jawaban: -((-3)2 – 4(2/5)(15))/4(2/5) = -(9 – 24)/(-8/25) = -375/85.
c. y = -3/4x2 + 7x – 18.