solve the equation: -2 + 5 + 8....+ x = 155
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Answered by
10
-2+13+x=155
11+x=155
x=155-11
x=144
Done!!
11+x=155
x=155-11
x=144
Done!!
AYUSHI3333:
wrong answer !!!
m not arguing if u r thinking.....m only telling that why r u adding x ??? it's an equation of A.P......it's not that simple equation...it's an A.P
Yeah....m also going to tell him /her....that it's wrong
Answered by
8
hello there!!!!
here , first term , a = 2
a2 = 5. a3 = 8
Common difference , d = a2 - a1 = 5 -2 = 3
a3 - a2 = 8-5 = 3
an =x
Sn = 155
Sn=1/2n [ 2a + (n-1) d ]
155=1/2x [2×2 + ( x-1)3]
155 × 2 = x [ 4 + 3x -3 ]
310 = x [ 3x +1 ]
310 = 3x² + x
3x² + x = 310
3x ( x +1 ) = 310
3x = 310 , x+1 = 310
x = 13.33. x = 309
hope it helps you....
here , first term , a = 2
a2 = 5. a3 = 8
Common difference , d = a2 - a1 = 5 -2 = 3
a3 - a2 = 8-5 = 3
an =x
Sn = 155
Sn=1/2n [ 2a + (n-1) d ]
155=1/2x [2×2 + ( x-1)3]
155 × 2 = x [ 4 + 3x -3 ]
310 = x [ 3x +1 ]
310 = 3x² + x
3x² + x = 310
3x ( x +1 ) = 310
3x = 310 , x+1 = 310
x = 13.33. x = 309
hope it helps you....
hello Friend !!! I think the answer is wrong
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