The answer is option B, if this helped mark me the brainiest!!
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:

Step-by-step explanation:
Because we are told equivalent expressions for y and z we can plug those in to 2(y+z).

Then simplify by combining like terms of the expressions. Values ending in x^2 can be combined with each other.

Now we can distribute the 2 by multiplying each value in the parentheses by 2.

Answer:
Total length of string required in yards
yards
Step-by-step explanation:
The length of the string attached with each balloon is equal to
feet
In the party total number of balloon used is equal to
balloons
The total length of the string required
Length of string used in one balloon * total number of balloons
feet
1 feet is equal to 13 yards
Total length of string required in yards
yards