At a school supply stołe, 5 packs of pencil and 7 packs of paper costs $22.25. At the same store, 8 packs of pencils and 2 packs of paper costs $14.90. How much is one pack of each?

1. ∠1 is complementary to ∠2 and ∠3 is complementary to ∠2. subtraction property of equality 2. m∠1 + m∠2 = 90 and m∠3 + m∠2 = 90 substitution 3. m∠1 + m∠2 = m∠3 + m∠2 definition of complementary 4. m∠1 = m∠3 given