Answer:
Sum of the first 15 terms = -405
Step-by-step explanation:
a + 3d = -15 (1)
a + 8d = -30 (2)
Where,
a = first term
d = common difference
n = number of terms
Subtract (1) from (1)
8d - 3d = -30 - (-15)
5d = -30 + 15
5d = -15
d = -15/5
= -3
d = -3
Substitute d = -3 into (1)
a + 3d = -15
a + 3(-3) = -15
a - 9 = -15
a = -15 + 9
a = -6
Sum of the first 15 terms
S = n/2[2a + (n − 1) × d]
= 15/2 {2×-6 + (15-1)-3}
= 7.5{-12 + (14)-3}
= 7.5{ -12 - 42}
= 7.5{-54}
= -405
Sum of the first 15 terms = -405
Do sin(90)*13/15 which gives you 0.87 then do inverse of sin-1(0.87) which angle A = 60.45 degrees
The answer is 3.2
hope it helps ya
<em>16+y=24, What is y?</em>
<em />
<em />
When solving an equation, we need to make sure that all variables are on one side and all numbers are on the other side.
Since we have numbers on both sides, we need to move all of them to one side:-
<h3>Good luck with your studies.</h3>
Answer:
C
Step-by-step explanation:
There is not enough information
