Question

$\frac{a(3 + a)}{3} \leqslant \frac{z(a - 1) {}^{2} }{15} - \frac{(a - 1)(4 - a)}{5} + \frac{1}{5}$
can anyone help me?​

Answer 1

a= 15+z+ square root 17(z+15)/ z-2
z=2a^2/(a-1)^2 + 30a/(a-1)^2 - 15/(a-1)^2