Question

solve this plz
From Class 10th Maths Chapter 5​

Answer 1

Answer:

n=18

Step-by-step explanation:

n/2[108+(n-1)×-3]=513

n[108+3n+3]=513×2

108n+3n²+3n= 513×2

3(36n+n²+n)=513×2

n²+36n+n= 513×2/3

n²+37n=171×2

n²+37n-342=0

n²+(19+18)n-342=0

n²+19n+18n_342=0

n(n+19)-18(n+19)=0

(n+19)(n-18)=0

n+19=0. n-18=0.

n=-19. n=18