Question

Hey friends please help me in this. 1+7+13+...+x=1160. Then find the value of x.​

Answer 1

Step-by-step explanation:

$x = 1 + (n - 1)6 \\ = 1 + 6n - 6 \\ = 6n - 5 \: \\ n = \frac{x + 5}{6} \\ \\ s = \frac{n}{2} (1 + x) \\ 1160 = \frac{n}{2} (1 + 6n - 5) \\ 1160 = \frac{n}{2} (6n - 4) \\ 1160 = n(3n - 2) \\ 3 {n}^{2} - 2n - 1160 = 0 \\ 3 {( \frac{x + 5}{6}) }^{2} - 2( \frac{x + 5}{6} ) - 1160 = 0 \\ 3( {x + 5})^{2} - 12(x + 5) - 1160 = 0$

Answer 2

Step-by-step explanation:

Step-by-step explanation:

\begin{lgathered}x = 1 + (n - 1)6 \\ = 1 + 6n - 6 \\ = 6n - 5 \: \\ n = \frac{x + 5}{6} \\ \\ s = \frac{n}{2} (1 + x) \\ 1160 = \frac{n}{2} (1 + 6n - 5) \\ 1160 = \frac{n}{2} (6n - 4) \\ 1160 = n(3n - 2) \\ 3 {n}^{2} - 2n - 1160 = 0 \\ 3 {( \frac{x + 5}{6}) }^{2} - 2( \frac{x + 5}{6} ) - 1160 = 0 \\ 3( {x + 5})^{2} - 12(x + 5) - 1160 = 0\end{lgathered}

x=1+(n−1)6

=1+6n−6

=6n−5

n=

6

x+5

s=

2

n

(1+x)j

1160=

2

n

(1+6n−5)

1160=

2

n

(6n−4)

1160=n(3n−2)

3n

2

−2n−1160=0

3(

6

x+5

)

2

−2(

6

x+5

)−1160=0

3(x+5)

2

−12(x+5)−1160=0