[tex]\mathfrak{\huge{\orange{\underline{\underline{AnSwEr:-}}}}}[/tex]
Actually Welcome to the Concept of the inequalities.
==> -2z +10z -7 > = 2z -9z -4
=> 8z - 7 >= -7z -4
=> 8z +7z >= -4+7
=> 15z >= 3
=> z >= 3/15
===>
[tex]z \: \geqslant \frac{1}{5} [/tex]