Step-by-step explanation:
subtract 21 from both sides
x2+2x+7-21=21-21
x2+2x+14=0
use quadratic equation
x=(-3+-(b^2-4ac)^1/2)/2a
in our equation a=1,b=2and c=14
(-2+-(14+56)^1/2)/2
x=-1+(60^1/2)/2
there is only one positive answer and it is 2.87
