15x1000+4x100+9x1
I belive that is edpanded notation.
To start, we need to distribute
multiply 2x by <em>everything</em> in the parenthesis
2x (5 + 3x) - x
2x × 5 = 10x
2x × 3x = 6x²
now we have...
10x + 6x² - x
<em>simplify </em>
<u>6x² + 9x </u>
the coefficient of x is 9!
If you're doing probabilities, there is a 1:6 chance on both (im guessing dont trust me i did probabilities a long time ago)