A sports store I'd having a sale on soccer balls. A soccer coach purchases 10 soccer balls and 2 soccers bags for $155. Another scorer coach purchases 12 soccer balls and 3 soccer bags for $189. What is the cost of a soccer ball and the cost of a soccer ball ?

- The price of a soccer ball is $14.5

- The price of a soccer bag is $5

Step-by-step explanation:

To solve this problem, we call:

s = the price of a single soccer ball

b = the price of a soccer bag

We have:

1) A soccer coach purchases 10 soccer balls and 2 soccers bags for $155: so we can write

(1)

2) Another scorer coach purchases 12 soccer balls and 3 soccer bags for $189: so we can write

(2)

So we have a system of two equations in two unknown variables:

We solve it by multiplying eq.(1) by 3 and eq(2) by 2, and we get:

Now we substract eq(2) from eq(1) and we get:

So

And by using eq(1) we also find the value of b:

So:

- The price of a soccer ball is $14.5

- The price of a soccer bag is $5

answer is the third choice:

3x^5+4x^4+x^3+2x^2-10x-7=0

step-by-step explanation: