35=n(n-3)/2

Solution for 35=n(n-3)/2 equation:

35=n(n-3)/2

We move all terms to the left:

35-(n(n-3)/2)=0

We multiply all the terms by the denominator


-(n(n-3)+35*2)=0


We calculate terms in parentheses: -(n(n-3)+35*2), so:

n(n-3)+35*2

We add all the numbers together, and all the variables

n(n-3)+70

We multiply parentheses

n^2-3n+70

Back to the equation:

-(n^2-3n+70)


We get rid of parentheses

-n^2+3n-70=0

We add all the numbers together, and all the variables

-1n^2+3n-70=0

a = -1; b = 3; c = -70;
Δ = b2-4ac
Δ = 32-4·(-1)·(-70)
Δ = -271
Delta is less than zero, so there is no solution for the equation