Given sequence:
-2,-7,-12 ,..
Unknown;
Find the sum of the first 20 terms = ?
Solution:
The sequence is -2,-7,-12 ,..
To find he sum of n-terms of a sequence, we use the expression below;
Sₙ = 
where n is the number of terms = 20
a is the first term = -2
d is the common difference= -7 - (-)2 = -5
Now input the parameters and solve;
Sₙ = 
Sₙ = 10(-4 + -5(19)) = 10(-99) = -990
The sum of the first 20 terms of the sequence is -990
Let All angles be x times multiplied to ratio , so we"ll get :-
2x + 3x + 4x + 5x + 6x = 540°
20x = 540
x = 540/20
⇒ x = 27 ,
so angles are :-
⇒ 2x = 2×27 = 54°
⇒ 3x = 3×27 = 81°
⇒ 4x = 4×27 = 108°
⇒ 5x = 5×27 = 135°
⇒ 6x = 6×27 = 162°
Hence 162° is the greatest angle
He paid $643.5 for it originally
585 x .1 = 58.5
585+58.5= 643.5
hope this helps
Answer:
the answer is 5x
Step-by-step explanation: