A deposit of $700$ is made at time $t=3\mathrm{.}25$ and another deposit of $950$ is made at time $t=5.$ A withdrawal of $x$ is made at time $t=8.$ Immediately after the withdrawal, $100$ is left in the account.

The account carries ${}^{(4)}=6\%$ between times $t=0$ and $t=3\mathrm{.}5,d^{(2)}=7\%$ between times $3\mathrm{.}5$ and $4\mathrm{.}5,$ and a simple annual interest rate of $=4\%$ between times $4\mathrm{.}5$ and $10.$

Find $x.$