Question

if X y and z are four consecutive term of an a.p then find X and y in term of b and c
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Answer 1

Answer:

ANSWER

Let the terms be a−3d,a−d,a+d,a+3d.

Given, Sum =20

⇒a−3d+a−d+a+d+a+3d=20

⇒4a=20

⇒a=5

Also given, sum of squares =120

⇒(a−3d)

2

+(a−d)

2

+(a+d)

2

+(a+3d)

2

=120

⇒(5−3d)

2

+(5−d)

2

+(5+d)

2

+(5+3d)

2

=120

⇒25−30d+9d2+25−10d+d

2

+25+10d+d

2

⇒25+30d+9d

2

=120

⇒100+20d

2

=120

⇒20d

2

=20

⇒d

2

=1

⇒d=±1

The terms are a−3d,a−d,a+d,a+3d

Thus, 5−3,5−1,5+1,5+3

(i.e.) 2,4,6,8 or 8,6,4,2

Step-by-step explanation:

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