Measurement is when it yields the same values across repeated measurement of the same event.

The answer is reliable. A measure is assumed to have a high reliability if it yields parallel results under steady conditions. It is the characteristic of a set of test scores that relates to the quantity of accidental or random error from the measurement procedure that might be rooted in the scores. Marks that are highly reliable are precise, reproducible, and constant from one testing time to another. To be exact, if the testing method were to be repeated with a different group of test takers, fundamentally the same results would be gotten. 

5x+40

5(x + 8)

7x - 49

7(x - 7)

18x + 9

9(2x + 1)

15x - 10

5(3x - 2)

step-by-step explanation:

for number one all you have to do is factor 5 out of 5x + 40

for number 2 factor 7 out of 7x - 49

for number three factor 9 out of 18x + 9

for number four factor 5 out of 15x - 10

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.