Question

Find a and b such that
n
∑（ak+b）=8n×n+11n
k=1​

Answer 1

Hello,

a=16 , b=3

Explanation:

`\displaystyle \sum_(k=1)^n\ (ak+b)\\\\=a*(\sum_(k=1)^n\ k)+n*b\\\\=a*((n+1)*n)/(2)+n*b\\=(a*n^2)/(2) +a*n+n*b=8*n^2+11*n\\\\(a)/(2) =8\ \Longrightarrow\ a=16\\a*n+n*b=16*n+b*n=11*n\ \Longrightarrow\ b=11-8=3`