How to solve 2l ^ 2 = - 81

1. Factor the equation (x + 2)(x + 3) = 0. 2. Set each factor equal to zero: x + 2 = 0 and x + 3 = 0. 3. Solve for x: x = -2 and x = -3.

Solve 2l ^ 2 = - 81 | Equatix

Basic Math

Pre-Algebra

Algebra

Trigonometry

Calculus

Precalculus

Statistics

Finite Math

Linear Algebra

Chemistry

Question

$$2l^{2}=-81$$

Solve for l

$l=-\frac{9\sqrt{2}i}{2}\approx -0-6.363961031i$
$l=\frac{9\sqrt{2}i}{2}\approx 6.363961031i$

Steps by Finding Square Root

Steps Using the Quadratic Formula

Steps by Finding Square Root

Divide both sides by $2$.

$$l^{2}=-\frac{81}{2}$$

The equation is now solved.

$$l=\frac{9\sqrt{2}i}{2}$$ $$l=-\frac{9\sqrt{2}i}{2}$$

Steps Using the Quadratic Formula

Divide both sides by $2$.

$$l^{2}=-\frac{81}{2}$$

Add $\frac{81}{2}$ to both sides.

$$l^{2}+\frac{81}{2}=0$$

This equation is in standard form: $ax^{2}+bx+c=0$. Substitute $1$ for $a$, $0$ for $b$, and $\frac{81}{2}$ for $c$ in the quadratic formula, $\frac{-b±\sqrt{b^{2}-4ac}}{2a}$.

$$l=\frac{0±\sqrt{0^{2}-4\times \frac{81}{2}}}{2}$$

Square $0$.

$$l=\frac{0±\sqrt{-4\times \frac{81}{2}}}{2}$$

Multiply $-4$ times $\frac{81}{2}$.

$$l=\frac{0±\sqrt{-162}}{2}$$

Take the square root of $-162$.

$$l=\frac{0±9\sqrt{2}i}{2}$$

Now solve the equation $l=\frac{0±9\sqrt{2}i}{2}$ when $±$ is plus.

$$l=\frac{9\sqrt{2}i}{2}$$

Now solve the equation $l=\frac{0±9\sqrt{2}i}{2}$ when $±$ is minus.

$$l=-\frac{9\sqrt{2}i}{2}$$

The equation is now solved.

$$l=\frac{9\sqrt{2}i}{2}$$ $$l=-\frac{9\sqrt{2}i}{2}$$

Show Solution

Basic Math

Pre-Algebra

Algebra

Trigonometry

Calculus

Precalculus

Statistics

Finite Math

Linear Algebra

Chemistry

Example

Question

Solve for l

Steps by Finding Square Root

Steps Using the Quadratic Formula

Steps by Finding Square Root

Steps Using the Quadratic Formula