Im going to assume you know the formula.
sooo.
x= -11 +- √ (11)² -4 (1) (-15)
---------------------------------
2(1)
= -11 +- √121- (-60)
-------------------------
2
= -11 +- √181
-----------------
2
= -11 +- 13.45
-----------------
2
Either: Or:
X = -11 - 13.45
x = -11 + 13.45 ---------------
2
----- ----------
2
x = 1.23 x= -12.23