Answer:
Final answer is c. 15
Step-by-step explanation:
We need to find about what is the first term in the sequence for which d = -2 and a7 = 3
We will use nth term formula of arithmetic sequence.

we have been given a7 that means 7th term is 3
so plug n=7, d=-2 and a_n=3 into above formula




Hence final answer is c. 15
and 7 each time answer Is 78
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Find Slope
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4x + 2y = 2
2y= -4x + 2
y = -4/2 x + 2
y = -2x + 2
Slope = -2
Perpendicular slope = 1/2
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Insert slope into the general equation y = mx + c
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y = 1/2x + c
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Find y-intercept
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y = 1/2x + c
at (5,6)
6 = 1/2 (5) + c
6 = 5/2 + c
c = 6 - 5/2
c = 7/2
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Insert y-intercept into y = 1/2 x + c
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y = 1/2 x + 7/2
2y = x + 7
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Answer: 2y = x + 7
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