Question

Fancy goldfish x cost $3 each and common goldfish y cost $1 each.Graph the function y=20-3x to determine how many of each type of goldfish Tasha can buy for $20.

Answer 1

The pairs of goldfish Tasha can buy for $20 are
`(0,20), (1,17), (2,14),`

`(3,11),(4,8),(5,5),and (6,2)`

Explanation:

To find the how many type of goldfish that Tasha can buy for $20 is the set of positive ordered pairs.

Let x denote the number of fancy goldfish.

Let y denote the number of common goldfish.

To find how much goldfish can Tasha buy for $20 is to substitute the value for x in the equation
`y=20-3x`

Now, substituting
`x=0` in
`y=20-3x`, we get,

`y=20`

The ordered pair is
`(0,20)`

Similarly, substituting
`x=1`,

`y=20-3(1)\\y=20-3\\y=17`

For
`x=2`,

`y=20-6\\y=14`

For
`x=3`,

`y=20-9\\y=11`

For
`x=4`,

`y=20-12\\y=8`

For
`x=5`,

`y=20-15\\y=15`

For
`x=6`,

`y=20-18\\y=2`

Thus, the pairs of goldfish Tasha can buy for $20 are
`(0,20), (1,17), (2,14),`
`(3,11),(4,8),(5,5),and (6,2)`