a, C = x . $\frac{5}{7}$ – x + $\frac{1}{8}$ khi | x | = $\frac{1}{2}$ b, D = $\frac{3}{7}$ . x + $\frac{8}{3}$ – x khi | x | = 6
a, C = x . $\frac{5}{7}$ – x + $\frac{1}{8}$ khi | x | = $\frac{1}{2}$ b, D = $\frac{3}{7}$ . x + $\frac{8}{3}$ – x khi | x | = 6