I’m pretty sure a is always and b is sometimes.
Answer: a = 18
explanation:
2(a + 10) = 56 -> distribute the 2
2a + 20 = 56 -> subtract 20 from both sides
2a = 56 - 20
2a = 36 -> divide both sides by 2
a = 18
well, we know the piece-wise function is 
hmmm so what's f(-1), namely what is f(x) when x = -1?
well, when x = -1, hmm -1 is less than 0, so the subfunction that applies to that will be when "x" is less than 0, namely the part of 7x + 10, so we can say
f(-1) = 7(-1) + 10
f(-1) = 3
so hmm what's f(0) or namely, what's f(x) when x = 0?
well, what subfunction applies when x = 0? well, it has to be the subfunction with "x greater or <u>equals</u> to 0", x ⩾ 0, so then is 7x + 20
f(0) = 7(0) + 20
f(0) = 20.
Answer:
A. m(-1)^(n-1)
Step-by-step explanation:
The degree of m doesn't change so none of the expressions with n as an exponent of m can possibly be correct. That leaves only choice A.
_____
You will find that when alternating signs are required, the term (-1)^n will be a factor. An offset of ±1 can be added to the n to make the initial sign be what you want. Here we want +1 for n=1, so an exponent of (n-1) is appropriate.