Twice the difference between 6 times h and 3 give 30

Can someone me and do the problem plz so i can understand it more better

Asandwich shop has 18 tables. each table seats up to 4 people. to find the greatest number of people that can be seated, you can solve p4 ≤ 18. which step is the best way to solve the inequality? plz asap i repeat plz

Urgent? will give brainliest given that the blue triangle is a right triangle, which expression correctly gives the area of the red square? a) a2 + b2 b) a2 - b2 c) a2 - c2 d) c2 - a2