9514 1404 393
Answer:
B. 4
Step-by-step explanation:
Equating exponents, we have ...
2x +7 = 15
2x = 8 . . . . . subtract 7
x = 4 . . . . . . divide by 2
The equation is true when the value of x is 4.
<em>The</em><em> </em><em>answer</em><em> </em><em>is</em><em> </em><em>in</em><em> </em><em>attached</em><em> </em><em>picture</em><em>.</em>
<em>Hope</em><em> </em><em>this</em><em> </em><em>will</em><em> </em><em>help</em><em> </em><em>u</em><em>.</em><em>.</em><em>.</em><em>.</em>
Answer:
Although the notation is sloppy, I will assume based on former questions of the same that "∑n=15[5(−2)^n−1]" translates mathematically to . Please correct me, though, if this in incorrect.
Anyway, there is neat formula that will deal with question very quickly. It is the following:
Sn is the sum of the geometric series
a1 is the first term in the series
r is the common ratio
n is the number of terms in the finite geometric series
Let's use this formula to our advantage! However, there are two variables that we do not know: a1 and n. Let's start with a1.The first term in the series is when n=1, so let's determine what that is.