X2 + 8X +17=0

Question

Answer in the form a + bi

Answer 1

x^2 + 8x + 17 = 0

 

Use equation      ax^2 + bx + c = 0

 

then put numbers into quadratic formula

x = (-b +/- (b^2 - 4ac)^(1/2)) / 2a

And so in this case

 

a=1  b=8  c=17

 

x = ((-8 +/- (8^2 - 4 x 1 x 17)^(1/2)) / (2 x 1)

 

x = ((-8 +/- (64 - 68)^(1/2)) / 2

 

x = -2 +/- ((-4)^(1/2)) / 2

 

x = -2 +/- (2i) / 2

 

so x = - 2 + i  and x = - 2 - i

where a = - 2 and b = -1, 1