$8\mathrm{.}29$ Three routes connect an origin$-$destination parr performance functions $t_1=5+1\mathrm{.}5x_1,t_2=12+3x_2,$ and $t_3=2+0\mathrm{.}2x_3^2($with $\text{'}$s in minutes and $x^{\text{'}}\text{'}$s in thousands of vehicles per hour$).$ Determine user$-$equilibrium flows if $q=4300ve\frac{h}{h}.$