You can answer this question by plugging the given values into point-slope form, which is y - y_{1} = m (x - x_{1}). M will represent slope and x_{1} and y_{1} will represent the x and y coordinates.
y - y_{1} = m (x - x_{1}) Substitute in the values
y - (-5) = 4 (m - 4) Cancel out the -(-5)
y + 5 = 4 (m - 4) Use the Distributive Property
y + 5 = 4m - 16 Subtract 5 from both sides
y = 4m - 21
To work out the profit, firstly, you have to work out the cost of buying them, which is $15 multiplied by 100, which is $1500. You then have to work out what he sold them all at, which is $29.99 multiplied by 100, which is $2999. You then have to subtract $1500 from $2999, giving you $1499. Therefore, Ace made $1499 in profit.
Hope this helps :)
I honestly don't know if this is correct but it might be i think its the middle one y=f(x)=x to the second power
1)360 (400*.9)
2)342 (380*.9)
3)119 (140*.85)
4)28 (35*.8)
