Answer:
x=10
Step-by-step explanation:
The two triangles are similar since each triangle is the same shape of right triangle but different sizes. To find x, write a proportion between two equal ratios of side lengths.

Solve by cross multiplying.
28(3x) = 20(4x+2)
84x = 80x + 40
4x = 40
x=10
1.D 2. A 3.C 4.D
1 Is the monomial as it only contains one expression.
2. Is the difference of squares because something squared minus something squared.
3. Is standard because it is of the form

4. We know D is the not the monomial simply because its power is negative which means it does not fit the definition of a polynomial.
Seems like a wordplay question.
A "scale" is used for measuring length.
A different sort of "scale" is used for measuring mass.

ρ - density, m - mass, V - volume
Liquid A:

Liquid B:

Liquid C:

The density of liquid C is approximately 0.96 g/cm³.