What is the definition of a closed dot on a graph

A closed (solid) dot means the endpoint is included in the curve and an open dot means it isn't. It's like the difference between "less than or equal to" and "less than". If the inequality is "strict" ( < or > ), we use an open dot to indicate that the endpoint of the ray is not part of the solution. For the other types of inequalities ( ≤ and ≥ ), we use a closed dot to indicate that the endpoint is part of the solution.

Step-by-step explanation:

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so:

i think it is everything has to equal 180 so, if i correct 4=c. 6=d. 8=a. 7=b. and the last question would be c. because they are parallel lines and they are congruent.

step-by-step explanation:

the reason everything has to equal to 180 is because that is how it works. i'm guessing that is its rule. 4 and 8 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 6 and 7 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 60+60 is 180. so, now you have your answer