He bought 200 of them
200*2.80=$560
marked up 90%
90% of 560=0.9*560=504
560+504=1064
he sold all 200 for a total of 1064, or an average price of $5.32 each
I hope this is what you were looking for.
(2x-3)(x+5)
Use foil to simplify, First multiply together the first terms of the pairs, then the outer terms, the middle terms, and finally the last terms. Then combine like terms.
2x^2+10x-3x-15 equals 2x^2+7x-15
Multiply the numbers on the major axis which are 2 and -9 to get -18. Subtract from that 3*4 = 12. So -18-12 = -30. That's the determinant.
C. "David's equation is correct, because their spending will be multiplied by the number of months and then subtracted from their savings"
they are technically saying "Look we have 12,350 to use. How long (y) will the savings (12,350) last after using 240 each month (x)
so the amount they use *PER* month gets subtracted from the savings because they are using that money to pay with
Hope this helps :)
