The values $of$ the function $z=f(x,y)=y^7-xy+x^7$ change from the point $(a,b)=(1,-1)to$ the point $(a+x,b+y)=(0\mathrm{.}95,-0\mathrm{.}96).$

Find the following quantities:

$x=$

$y=$

Find $z,$ ensuring that the answer you enter $is$ accurate $to4DP.$

Compute $dz$ assuming that $dx=x$ and $dy=y.$ Ensure your answer $is$ accurate $to3DP.$

$dz=$