Question

Solve. |9x| = 81 ?????????

Answer 1

Answer:

x = 9, x = -9

alternatively:

x = {9, -9}

Step-by-step explanation:

how absolute value works is you split it into 2 equations:

9x = 81, and 9x = -81

9x = 81

x = 81/9

x = 9

9x = -81

x = -81/9

x = -9

Answer 2

Answer:

x = 9 Or x = -9

Step-by-step explanation:

The lines on the side mean that the number is it’s ‘absolute value’.

This means whatever number it is, it is positive.

For example if the number was -2, it would be 2.

Knowing this, the number inside can be positive or negative.

Now since we know, we can solve the equation:

(Slashes show the lines meaning absolute value)

/9x/ = 81

divide each side by 9 so the x is alone:

/9x/÷9 = 81÷9

/x/ = 9

x = 9

Or

x = -9

We can check by substituting the 9 in:

/9·9/ = 81

/81/ = 81

81 = 81

or

/9·(-9)/ = 81

/-81/ = 81

81 = 81