Page 187 - Math Course 2 (Book 1)

Systems of Equations: Substitution

Your Turn!

Write and Solve a System of Equations
CHEMISTRY
Mikhail needs 10 milliliters of 25% HCl (hydrochloric acid) solution for a chemistry experiment. There is a
bottle of 10% HCl solution and a bottle of 40% HCl solution in the lab. How much of each solution should
he use to obtain the required amount of 25% HCl solution?

A. 0 mL of 10% solution, 10 mL of 40% solution
B. 6 mL of 10% solution, 4 mL of 40% solution
C. 5 mL of 10% solution, 5 mL of 40% solution
D. 3 mL of 10% solution, 7 mL of 40% solution

Answer

Use substitution to solve each system of equations. If the
Skill Practice! system does not have exactly one solution, state whether it
has no solution or inf nitely many solutions.

1. y = 4x 2. y = 2x
x + y = 5 x + 3y = –14

3. y = 3x 4. x = –4y
2x + y = 15 3x + 2y = 20

5. y = x – 1 6. x = y – 7
x + y = 3 x + 8y = 2

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