Download Math 123B Fall 2015 Instructor: Lan Ch7 Test B

Math 123B Fall 2015 Instructor: Lan
Ch7 Test B
Name_____________________________________
Directions: Show all work in the space provided. Write answer on line or graph provided. Closed books and notes. Scientific
calculator is allowed. Graphing calculators, cell phones, smart phones, laptops, iPads, tablets, etc. are not allowed.______
Determine whether the ordered pair is a solution of the system of linear equations. Show work (2 pts), Answer (2 pts)
1) (6, 3);
4pts.
YES
NO
4x + y = 21
3x + 4y = 6
2) (1, 4);
2x + y = 6
4x + 2y = 12
4pts.
YES
NO
Solve the system of equations by graphing. Graphing correct lines (2 points each), Point of intersection (2 points).
x - 2y = 1
6pts. Pt of intersection __________________
3)
3x + 2y = 11
B1
Solve the system of equations by graphing. Graphing correct lines (2 points each), Point of intersection (2 points).
6pts. Pt of intersection ________________
4) 2x + y = 3
y = -1
Solve the systems of equations by the substitution method. Show answers using ordered pairs.
5pts. 5) __________________
5) x + y = -25
y = 4x
6)
x + 3y = 17
7x + 2y = 62
5pts. 6) __________________
B2
Solve the system of equations by the substitution method. Show answer using ordered pair.
5pts. 7) __________________
7) 5y = x - 14
7x - 6y = 11
Solve the systems of equations by the addition method. Show answers using ordered pairs.
5pts. 8) ________________
8) x - 5y = -42
3x - 6y = -45
9)
3x - 5y = 5
2x - 3y = 5
10) -3x + 5y = 13
7x + 3y = -1
5pts. 9) __________________
5pts. 10) __________________
B3
Solve the 3x3 systems of equation using substitution or elimination. Show answers using ordered triples.
11)
x -y +z = 3
8pts. 11) __________________
x + y + z = -3
x + y - z = -7
12)
5x + 2y + z = 1
3x - 5y - z = -21
5x + y + 3z = -7
8pts. 12) __________________
B4
Questions 13 & 14. Setup, solve and show each step clearly. 3 points for setup, 3 points for work, and 2 pts. for solution.
13) Devon purchased tickets to an air show for 6 adults and 2 children. The total cost was $178. The cost of a child's
ticket was $3 less than the cost of an adult's ticket. Find the price of an adult's ticket and a child's ticket.
8pts. A) __________________
C) __________________
14) One number is four more than a second number. Two times the first number is 2 more than four times the
second number. Find the numbers.
8pts. 14) __________________
B5
Questions 15 & 16. Setup, solve and show each step clearly. 4 points for setup, 3 points for work, and 2 pts. for solution.
15) A chemist needs 120 milliliters of a 66% solution but has only 63% and 75% solutions available. Find how many
milliliters of each that should be mixed to get the desired solution.
9pts. 15) 1st____________ 2nd____________
16) A certain aircraft can fly 720 miles with the wind in 3 hours and travel the same distance against the wind in 8
hours. What is the speed of the wind?
9pts. 16) __________________
B6
Answer Key
Testname: MATH123B CH7TESTB HEMENWAY
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
13)
14)
15)
16)
No
Yes
(3, 1)
(2, -1)
(-5, -20)
(8, 3)
(-1, -3)
(3, 9)
(10, 5)
(-1, 2)
(-2, -3, 2)
(-1, 4, -2)
adult's ticket: $23; child's ticket: $20
7 and 3
90 ml of 63%; 30 ml of 75%
75 mph
B7