Find the value of x, if 2+4+6+…+x=650.

Answer

N/a

Explanation

Here a=2, d=4-2=6-4=2
`"Let "S_(n)=650`
`rArr " "(n)/(2)[2a+(n-1)d]=650`
`rArr " "(n)/(2)[2xx2+(n-1).2]=650`
`rArr " "n^(2)+n-650=0`
`rArr " "(n+26)(n-25)=0`
`rArr " "n+26=0 or n-25=0`
`rArr " "n=-26 or n=25`
But 'n' cannot be negative
`therefore" "n=25`
`"Now, "x=T_(25)=a+(25-1)d`
`=2+24xx2`
`=50.`