Question

Solve 3x2 = 27.

a
±3

b
±9

c
square root 3
d
3 times square root 3

Answer 1

The solution of the equation is :

↬ choice A

Solution:

Our equation is:
`\sf{3x^2=27}`.

To solve it, we should isolate the x. So I begin by dividing each side by 3:

`\sf{3x^2=27}`

`\sf{x^2=9}`

Now, to get rid of the square on top of the x, I take the square-root of each side; the square-root and the square will cancel out on the left.

Keep in mind that once you take the square root of a number, you end up with TWO solutions.

So the result is:

`\sf{x=3, x=-3}`, which can be rewritten as x = ± 3

Hence, x = ± 3

Answer 2

Hello!

3x² = 27

3x²/3 = 27/3

x² = 9

√x² = ±√9

x = ±3