First one simplifies to 2x + 6 = 2x + 7 which can't be true so this one has No Solution.
Same applies to the second equation ( 5x + 15 = 5x - 15) No solution
also the last one has no solution because it simplifies to 4x + 20 = 4x + 19
Answer:

Step-by-step explanation:
Given expression:

Remove parentheses:

Collect like terms:

Combine like terms:

Answer:
The Null hypothesis is a claim the researcher is trying to disprove. (I think)
Step-by-step explanation:
The null hypothesis states that there is no relationship between the two variables being studied (one variable does not affect the other). It states results are due to chance and are not significant in terms of supporting the idea being investigated.
the answer is C. because it is the only one that does not contain a common factor :)
Answer: -3.17
Step-by-step explanation:
-3.6 + 0.43 = -3.17