how many real roots does the quadratic equation x2+5x+7=0?


Sagot :

It's discriminant is:
5² - 4(1)(7)
= 25-28
= -3

Hence, b²-4ac is negative then it has two imaginary solutions or no real roots.
[tex]x^2+5x+7=0 \\ \\a=1, \ b=5 ,\ \ c=7 \\ \\\Delta =b^2-4ac =5^2-4\cdot 1\cdot 7=25-28=-3\\\\If \ \Delta <0, \ then \ roots \ are \imaginary \ (non-real)[/tex]