Equations in x and y: write one for a story, and check a solution pair

Answer Key - Grade 9 Math Worksheet

Circle the best answer, or write your answer on the line.

1. Read this first

   Use this

   Input–output table (x | y). Each pair is one row; a solution is a row that makes both sides equal.

2. 1.

   In math club, Ari tests pairs in 3x + 2y = 18. Which pair is a solution?

   • (3, 4)
   • (10, 8)
   • (4, 3)
3. 2.

   Tala tests pairs from a puzzle book for x + 2y = 3. Which pair is a solution?

   • (5, 1)
   • (7, -4)
   • (5, -1)
   • (-1, 5)
4. 3.

   Jun tests pairs for the rule 3x − 2y = 5. Which pair is a solution?

   • (2, 3)
   • (3, 2)
   • (4, 1)
5. 4.

   The line is 2x + 5y = 40. Bo's line is 2x + 5y = 40. The pair (5, ?) is on the line. What number goes in place of the ?

   6
6. 5.

   The line is 4x + 3y = 33. Milo's line is 4x + 3y = 33. The pair (3, ?) is on the line. What number goes in place of the ?

   7
7. 6.

   The line is 5x − 2y = 14. Zee's line is 5x − 2y = 14. The pair (4, ?) is on the line. What number goes in place of the ?

   3

8. Use the table

   count	amount
   c	3c
   g	2g

9. 7.

   Ren buys c notebooks at $3 each and g pens at $2 each, and spends $17. What equation fits the story, using c and g?

   3c + 2g = 17
10. 8.

    Esme spends 20 tokens on h rides at 4 tokens each and g games at 2 tokens each. What equation fits the story, using h and g?

    4h + 2g = 20
11. 9.

    Noah packs q potato bags of 5 kg each and c carrot bags of 3 kg each, 29 kg in all. What equation fits the story, using q and c?

    5q + 3c = 29
12. 10.

    Ari practices s songs at 15 minutes each and w warm-ups at 10 minutes each, 60 minutes in all. What equation fits the story, using s and w?

    15s + 10w = 60