Question

How do you solve `3x^2 - 123 = 0`?

Answer 1

`x=±sqrt41`

Explanation:

The first step is to take out a common factor of 3.

`3x^2-123=0rArr3(x^2-41)=0`

now `x^2-41=0rArrx^2=41`

Taking the 'square root' of both sides

`rArrsqrt(x^2)=±sqrt41rArrx=±sqrt41`

Answer 2

`x=+-sqrt41`

Explanation:

Isolate `x` to find its value

`color(blue)(3x^2-123=0`

Add `123` both sides

`rarr3x^2-123+123=0+123`

`rarr3x^2=123`

Divide both sides by `3`

`rarr(cancel3x^2)/cancel3=123/3`

`rarrx^2=41`

Take the square root of both sides

And also remember that,when taking the square root of a number,it can be a positive or negative number

Positive or negative - `+-`

`rarrsqrt(x^2)=+-sqrt41`

`color(green)(rArrx=+-sqrt41`