kakak bantu tolong jawab ini ya

[tex]5. \: a + b + c = 5...(1) \\ \: 4a + 2b + c = 1...(2) \\ \: 4a - 2b + c = - 7 ...(3)\\(2.3) \: 4b = 8 \: \: \: \: b = 2 \\ (1.3) - 3a = 6 \: \: \: \: a = - 2 \: \: \: \: c = 5 \\ y = - 2 {x}^{2} + 2x + 5[/tex]
[tex]6. \: \: y = a {(x - xp)}^{2} + yp \\ - 8 = a {(0 - ( - 4))}^{2} + 0 \\ - 8 = 16a \\ a = - \frac{1}{2} \\ y = - \frac{1}{2} {(x + 4)}^{2} = - \frac{1}{2} ( {x}^{2} + 8x + 16) = - \frac{1}{2} {x}^{2} - 4x - 8[/tex]
no.7 sama caranya dengan no.5