Explicație pas cu pas:
a) A(-3; -15)
[tex]h( - 3) = - 3a - 2a = - 15 \\ - 5a = - 15 \\ a = \frac{ - 15}{ - 5} = > a = 3[/tex]
b) B(a; -1)
[tex]h(a) = a \times a - 2a = - 1 \\ {a}^{2} - 2a = - 1 \\ {a}^{2} - 2a + 1 = 0 \\ {a }^{2} - 2 \times a \times 1 + {1}^{2} = 0 \\ (a - 1) ^{2} = 0 \\ a - 1 = 0 \\ a = 1[/tex]
c) C (a+1; 6)
[tex]h(a + 1) = a(a + 1) - 2a = 6 \\ {a}^{2} + a - 2a = 6 \\ {a}^{2} - a = 6\\ {a}^{2} - a - 6 = 0 \\ a = 1 \\ b = - 1 \\ c = - 6 \\ delta = ( - 1) ^{2} - 4 \times 1 \times ( - 6) = \\ = 1 + 24 = 25 \\ a1 = \frac{1 + \sqrt{25} }{2 \times 1} = \frac{1 + 5}{2} = \frac{6}{2} = 3 \\ \\ a2 = \frac{1 - \sqrt{25} }{2} = \frac{1 - 5}{2} = \frac{ - 4}{2} = - 2[/tex]
