Find all solutions to the equation.
cos^2 x +2cosx+1=0

Icould really use some with this question.

Examine the two-step equation. − 7 4 + x 4 = 2 which property of operations allows you to add the same constant term to both sides? amultiplication property of equality bdivision property of equality caddition property of equality dsubtraction property of equality

Which function has an inverse function? a.f(x)= |x+3|/5 b. f(x)= x^5-3 c. f(x)= x^4/7+27 d. f(x)= 1/x²