t v = 88 ↓ t = 88 V {\displaystyle {\begin{aligned}&tv=88\\&\downarrow \\&\color {blue}t={\frac {88}{V}}\\\end{aligned}}}
81 − 3 v = ( v − 3 ) ( t − 2 ) 81 − 3 v = ( v − 3 ) ( 88 − 2 v v ) 81 v − 3 v 2 = 88 v − 2 v 2 − 264 + 6 v v 2 + 13 v − 264 = 0 − 13 ± 13 2 + 4 ∗ 264 2 − 13 ± 35 2 V = 22 2 = 11 {\displaystyle {\begin{aligned}&81-3v=(v-3)(t-2)\\&81-3v=(v-3)({\frac {88-2v}{v}})\\&81v-3v^{2}=88v-2v^{2}-264+6v\\&v^{2}+13v-264=0\\&{\frac {-13\pm {\sqrt {13^{2}+4*264}}}{2}}\\&{\frac {-13\pm 35}{2}}\\&\color {blue}V={\frac {22}{2}}=11\\\end{aligned}}}
