X2 + 2x + 5 = 0 solve with quadratic formula

x = -1 ± 2i

Step-by-step explanation:

The standard form of a quadratic equation is ax² + bx + c = 0, and the quadratic formula is x=  [−b ± √(b ² - 4ac) ] / 2a

In this case, a = 1, b = 2 and c = 5. Now you have to substitute in the quadratic formula:

x=  [−b ± √(b ² - 4ac) ] / 2a

x=  [−2 ± √(2 ² - 4*1*5) ] / 2*1

x=  [−2 ± √(4 - 20) ] / 2

x=  [−2 ± √(-16) ] / 2

Since the square root is negative, you have to use imaginary numbers to continue solving the equation. Remmber that √(-1) = i.

x=  [−2 ± √(-16) ] / 2

x=  [−2 ± √(16)i ] / 2

x=  [−2 ± 4i ] / 2

x1 =  [−2 + 4i ] / 2

x1 = -1 + 2i

x2 =  [−2 - 4i ] / 2

x2 = -1 - 2i

 So the answers of x are -1 ± 2i

e) none of the above because the measure of angle cba is 101°