Which two numbers will add up to 2 and when multiply gives us -280?

Answer 1

Let the numbers be 'm' & 'n'

Hence

m + n = 2

mn = - 280

It follows that m = 2 - n

Substitute

(2 - n)n = -280

Multiply out the brackets

2n - n^2 = -280

n^2 - 2n - 280 = 0

It is now in Quadratic form. Either use the Quadratic Eq'n or 'Complete the Square'.

n^2 - 2n = 280

(n - 1)^2 - (-1)^2 = 280

(n - 1)^2 = 281

Square root both sides

n -1= sqrt(281)

n = 1 +/- sqrt(281)