Draw two planes that intersect in line ET

I have no idea how to draw this please help me

Find the greatest common factor of -30x 4 yz 3 and 75x 4 z 2.

Marlow is comparing the prices of two trucks rental compaines company a charges $3 per hour and an addtional $75 as serivce charges company b charges $2 per hour and an additional $85 as serivce charges

Solve 3x-18=2y and 5x-6y=14 by elimination or substitution . show all !