The sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
Given,
18th term of an arithmetic sequence = 8.1
Common difference = d = 0.25.
<h3>What is an arithmetic sequence?</h3>
The sequence in which the difference between the consecutive term is constant.
The nth term is denoted by:
a_n = a + ( n - 1 ) d
The sum of an arithmetic sequence:
S_n = n/2 [ 2a + ( n - 1 ) d ]
Find the 18th term of the sequence.
18th term = 8.1
d = 0.25
8.1 = a + ( 18 - 1 ) 0.25
8.1 = a + 17 x 0.25
8.1 = a + 4.25
a = 8.1 - 4.25
a = 3.85
Find the sum of 20 terms.
S_20 = 20 / 2 [ 2 x 3.85 + ( 20 - 1 ) 0.25 ]
= 10 [ 7.7 + 19 x 0.25 ]
= 10 [ 7.7 + 4.75 ]
= 10 x 12.45
= 124.5
Thus the sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
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C. -10x+32
Explanation: Solve the problem
( -4(2x-8)-2x )
Observation : No two such factors can be found !!
Conclusion : Trinomial can not be factored
<span>Equation at the end of step 2 :</span> 6x2 - x - 4 = 0 <span>((2•3x2) - x) - 4 = 0
</span><span>Step 2 :</span>Trying to factor by splitting the middle term
<span> 2.1 </span> Factoring <span> 6x2-x-4</span>
The first term is, <span> <span>6x2</span> </span> its coefficient is <span> 6 </span>.
The middle term is, <span> -x </span> its coefficient is <span> -1 </span>.
The last term, "the constant", is <span> -4 </span>
Step-1 : Multiply the coefficient of the first term by the constant <span> <span> 6</span> • -4 = -24</span>
Step-2 : Find two factors of -24 whose sum equals the coefficient of the middle term, which is <span> -1 </span>.
<span><span> -24 + 1 = -23</span><span> -12 + 2 = -10</span><span> -8 + 3 = -5</span><span> -6 + 4 = -2</span><span> -4 + 6 = 2</span><span> -3 + 8 = 5</span><span> -2 + 12 = 10</span><span> -1 + 24 = 23
</span></span>
Observation : No two such factors can be found !!
Conclusion : Trinomial can not be factored
<span>Equation at the end of step 2 :</span><span> 6x2 - x - 4 = 0 </span>
Step-by-step explanation:
The Angle Addition Postulate de fusteer Key. Date ... 99° and MZLMF = 36º. Find m2LMN. 6) Find mZWDC if IZEDC = 145° and mZEDW= 61°. N of w. C ... 11) mZHGF = 16x + 4, m EGF = 110°,. 12) mZVUT = 175° ... a H, 16X+4=110 + 3x +11
-5m = -35
-5m/-5 = -35/-5
m = 7
Answer: m = 7