Question

Use any method to solve the equation. If necessary, round to the nearest hundredth.

Answer 1

We have that
9x² − 21 = 0

using a graph tool
see the attached figure

the solution is
x=-1.528----> -1.53
x=1.528---->  1.53

Answer 2

Answer:

$x_{1}=1.53\\x_{2}=-1.53$

Step-by-step explanation:

The given quadratic equation is

$9x^{2}-21=0$

To solve this equation, we just have to isolate the variable, because the quadratic expression has only one variable, the linear term is not present. So

$9x^{2} =21\\x^{2} =\frac{21}{9}$

Now, we apply a square root, to have the variable complete isolated

$\sqrt{x^{2} }=\sqrt{\frac{21}{9} } \\x=\±1.53$

Remember that all square roots have two results, one positive and one negative.

Therefore, the solutions for this equation are

$x_{1}=1.53\\x_{2}=-1.53$