Question

Graph x+3<1/2(4x-12)<20

Answer 1

$x+3 < \dfrac{1}{2}(4x-12) < 20\\\\x+3 < 2x-6 < 20$

$x+3 < 2x-6\ \wedge\ 2x-6 < 20\\\\x-2x < -6-3\ \wedge\ 2x < 20+6\\\\-x < -9 \ \wedge\ 2x < 26\\\\x > 9\ \wedge\ x < 13$

Look at the picture.