Exam 4: Systems of Equations

Write the word or phrase that best completes each statement or answers the question. -Adam has a total of 62 coins, all of which are either dimes or nickels. The total value of the coins is $5.35. Find the number of each type of coin.

work. Do not solve. -5x + 9y = -12 -4x - 4y = -32 A) Substitution B) Addition Answer: B Write the word or phrase that best completes each statement or answers the question. -A contractor mixes concrete from bags of pre-mix for small jobs. How many bags with 8% cement should he mix with 8 bags of 16% cement to produce a mix containing 12% cement?

Write the word or phrase that best completes each statement or answers the question. -Under what circumstances can a system of equations be solved more easily by graphing than be substitution?

Write the word or phrase that best completes each statement or answers the question. - x-y=3 x+y=2

Provide an appropriate response. -When solving a system of equations, you get x - 3 = x + 3. How many solutions are there?

Write the word or phrase that best completes each statement or answers the question. -5x - 2y = -1 x + 4y = 35

work. Do not solve. -5x + 9y = -12 -4x - 4y = -32 A) Substitution B) Addition Answer: B Write the word or phrase that best completes each statement or answers the question. --4x + 5y = A 4x - 3y = B For what values of A or B can this system of equations have (0, 0) as a solution?

Solve the problem. -The number of cars sold by a certain automobile manufacturer, y, in a particular year can be approximated by the equation y = -307x + 27,878, where x represents the number of years after 1990. The number of SUVs sold by the same automobile manufacturer, y, in a particular year can Be approximated by the equation y = 444x + 19,769, where x represents the number of years after 1990. In what year did this automobile manufacturer sell an equal number of cars and SUVs?

work. Do not solve. -5x + 9y = -12 -4x - 4y = -32 A) Substitution B) Addition Answer: B Write the word or phrase that best completes each statement or answers the question. -Write a system of equations that would be more easily solved using the substitution method than the addition method. Explain why substitution would be easier than addition.

Is the ordered pair a solution of the given system of equations? -A student was asked to find ordered pairs that solve the system of equations x + 2y = 3 -2x - 4y = -6. The student claims that (1, 1) and (-1, 2) are the only solutions. Is the student correct?

Write the word or phrase that best completes each statement or answers the question. - 2x+3y=5 6x=10+9y

work. Do not solve. -5x + 9y = -12 -4x - 4y = -32 A) Substitution B) Addition Answer: B Write the word or phrase that best completes each statement or answers the question. -Mardi received an inheritance of $70,000. She invested part at 10% and deposited the remainder in tax-free bonds at 9%. Her total annual income from the investments was $6600. Find the amount Invested at 10%.

Write the word or phrase that best completes each statement or answers the question. -A student argued that it is impossible to use the substitution method to determine if a system of equations has no solution or an infinite number of solutions. Is the student correct?

Write the word or phrase that best completes each statement or answers the question. - x+3y=3 2x=-6y+6

Write the word or phrase that best completes each statement or answers the question. - $x - 2 y = 1$ $- 7 x - 3 y = - 75$

Write the word or phrase that best completes each statement or answers the question. -Solve the following system of equations by first solving Equation (1) for x and then substituting for x in Equation (2). Then solve the system again by first solving Equation (1) for 2y and substituting for 2y in Equation (2). Which procedure do you prefer? Explain why you answered as you did. x + 2y = 6 (1) 3x + 2y = 4 (2)