Question

. Solve the equation ::: 1 + 4 + 7 + 10 +...+ x =287​

Answer 1

Answer:

gsgsbsjjalakwbsyshlaowiuwebnx znkahsvxjusbsgbdjs

Answer 2

Step-by-step explanation:

given

a=1

d=4−1=3

and,s  

n

​  

=287

Now,

s  

n

​  

=  

2

n

​  

(2a+(n−1)d)

⇒287=  

2

n

​  

(2×1+(n−1)3)

⇒287=  

2

n

​  

(2+3n−3)

⇒574=n(3n−1)

⇒574=3n  

2

−n

⇒3n  

2

−n−574=0

onsolvingthequadraticequatonusingformula

n=  

2a

−b±  

b  

2

−4ac

​  

 

​  

 

Wegetn=14&  

3

−41

​  

[doesnotexist]

so,n=14

Now,

s  

n

​  

=  

2

n

​  

(a+1)

⇒287=  

2

14

​  

(1+x)

⇒574=14(1+x)

​=1+x=41

=x=41−1

=40

​