All you have to do here is combine like terms.
5x + 9x = 14x
.5 - 2.5 = -2
14x - 2
The easiest way to determine the score is to use a calculator or spreadsheet and the appropriate probability function.
If you want the top 10%, the score corresponds to the 90th percentile. That score is 316.
If you want the top 15%, the score corresponds to the 85th percentile. That score is 313.
Tina bought 5 bottles of nail polish and 4 tubes of lip gloss.
The perpendicular equation is y = -3/2x - 4.
You can find this by first realizing that perpendicular lines have opposite and reciprocal slopes. So since it starts at 2/3 we flip it and make it a negative and the new slope is -3/2. Now we can use that and the point to get the y intercept using slope intercept form.
y = mx + b
5 = (-3/2)(-6) + b
5 = 9 + b
-4 = b
And now we can use our new slope and new intercept to model the equation.
y = -3/2x - 4