Use the quadratic formula to solve for \( x \). \[ 3 x^{2}+6 x=-1 \] Round your answer to the nearest hundredth. If there is more than one solution, separate them with commas. \( x=\square \)

Use factoring to solve the polynomial equation. \( a^{3}+2 a^{2}-9 a-18=0 \)

Complete the square by adding the correct missing term on the left, then factor as indicated: \( \left.\qquad x^{2}+7 x+\square\right)^{2} \)

Let \( f(x)=x^{2}+x-4 \), and \( g(x)=-2 \). Find all values for the variable \( x \), for which \( f(x)=g(x) \)

\( 3 x - 5 y ) ^ { 2 } = \)

Let \( f(x)=x^{2}+2 x \), and \( g(x)=3 x+20 \). Find all values for the variable \( x \), for which \( f(x)=g(x) \). \( x=\square \)