a(x-5)/4>x-4
0.25ax-1.25a>x-4
0.25ax+4>x+1.25a
0.25ax-x>1.25a-4
x(0.25a-1)>1.25a-4
x>(1.25a-4)/(0.25a-1)
x>(5a+16)/(a-4)
大于号视为大于等于号