Could someone translate this to words? ∅ ⊆ N

-1 ∉ N

and could someone name the property of these?

a(b + c) = ab + ac
t(sq) = (ts)q
n(1/n) = 1

Two corresponding sides of two similar triangles are 3cm and 5cm. the area of the first triangle is 12cm2. what is the area of the second triangle?

When you find the area of a triangle do you use in. or in2

Michael and imani go out to eat for lunch if their food and beverages cost 25.30 and there is an 8% meals tax how much is the bill