Răspuns:
[tex]f(x) = -1.5x^2 + 5x[/tex]
Explicație pas cu pas:
y = 2x - 12
x = -2
y = -4 -12 = -16
x = 4
y = 8 - 12 = -4
a < 0
[tex]\Delta = 0[/tex]
[tex]b^2 - 4ac = 0[/tex]
4a - 2b + c = -16
8a - 4b + 2c = -32
16a + 4b + c = -4
24a + 3c = -36
3(8a + c) = -36
8a + c = -12
c = -4(2a + 3)
[tex]a\times \frac{b^2}{a^2} + b\times \frac{-b}{a} + c = 0[/tex]
[tex]\frac{b^2 - b^2}{a} + c = 0[/tex]
[tex]c = 0[/tex]
0 = -4(2a + 3)
2a + 3 = 0
2a = -3
a = -3/2 = -1.5
-6 -2b + 0 = -16
-2b = -10
b = 5
[tex]f(x) = -1.5x^2 + 5x[/tex]
