378=x(x-1)/2

Solution for 378=x(x-1)/2 equation:

378=x(x-1)/2

We move all terms to the left:

378-(x(x-1)/2)=0

We multiply all the terms by the denominator


-(x(x-1)+378*2)=0


We calculate terms in parentheses: -(x(x-1)+378*2), so:

x(x-1)+378*2

We add all the numbers together, and all the variables

x(x-1)+756

We multiply parentheses

x^2-1x+756

Back to the equation:

-(x^2-1x+756)


We get rid of parentheses

-x^2+1x-756=0

We add all the numbers together, and all the variables

-1x^2+x-756=0

a = -1; b = 1; c = -756;
Δ = b2-4ac
Δ = 12-4·(-1)·(-756)
Δ = -3023
Delta is less than zero, so there is no solution for the equation