Determine whether the study described is a randomized experiment or an observational study. A math department chair wants to determine the effectiveness of online homework systems. She chooses four college algebra classes and assigns a different online homework system to three of the classes. One class does not use any online homework system. She administers a common pretest and final exam to measure the effectiveness.

the answer is 175.4379

step-by-step explanation:

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

-2x + 7 = 7

subtract 7 from both sides.

-2x = 0

divide both sides by -2.

x = 0

b. 2 and 4

step-by-step explanation: