Question

Solve the inequality. -z+20>z+20

Answer 1

$-z+20>z+20\\ -2z>0\\ z$

Answer 2

$-z+20 > z+20\ \ \ \ \ \ |subtract\ 20\ from\ both\ sides\\\\-z > z\ \ \ \ \ |add\ z\ to\ both\ sides\\\\0 > 2z\\\\2z < 0\ \ \ \ \ \ \ |divide\ both\ sides\ by\ 2\\\\z < 0\\\\z\in(-\infty;\ 0)$