Question

How do you solve `x(x+6)=-15` using the quadratic formula?

Answer 1

No real solutions, x>0

Explanation:

Expand boiii

`x(x+6)`

`x*x` = `x^2`

`x * 6` = `6x`

We have -15, bring that over to make + 15

so the equation is `x^2 + 6x + 15 = 0`

collect terms for the quadratic formula `(-b +- sqrt(b^2 - 4(a)(c)))/(2a)`
a is the number in front of `x^2`
b is the number in front of `x`
c is the number without an `x`, poor lonely number

a = 1
b = 6
c = 15
remember minuses matter, however there are none in this question.

so plug it in
`( -6 +- sqrt(6^2 - 4(1)(15)))/(2(1))`

put into your calculator as is, i'd suggest one from here: https://goo.gl/JtHwiA they are brilliant. (Casio 991ex)

This leaves a negative number in your square root, which means imaginary numbers.. No real solution is obtainable