Answer:
Step-by-step explanation:
You can make it by using division +/-. The keystrokes are
+
/
-
a = 13
b = -5
c = 1
x = [-(-5) +/- sqrt( (-5)^2 - 4*13*1) )] / 2
x = [ 5 +/- sqrt( 25 - 52) ] / 2
x = [ 5 +/- sqrt(-27)]/2
x = [5 +/- 3 sqrt(3)i ] / 2
x = 5/2 +/- 3/2 * sqrt(3) i
So x1 = 2.5 + 1.5 sqrt(3)i or
x2 = 2.5 - 1.5 sqrt(3)i
