Question

find x if { -4+ (-1+2+3+.......+x)} = 437

Answer 1

(-1+2+3+.....+x=437+4
add 2 on both side
2-1+2+3+.....+x=441+2=443
1+2+3+....+x=443
sum on first x natunarl no= x*(x+1)/2=443
x(x+1)=443*2=886
x^2+x-886=0
solve the quadratic