Name ________________________________________ Date __________________ Class__________________
LESSON
6-3
Practice C
Solving Systems by Elimination
Solve each system by elimination.
⎧x + y = 2
1. ⎨
⎩2x − y = 7
________________________
⎧−3x − 4y = −2
4. ⎨
⎩6x + 4y = 3
________________________
⎧ x + 6y = 1
7. ⎨
⎩2x − 3y = 32
________________________
⎧5x − 2y = −48
10. ⎨
⎩2x + 3y = −23
________________________
⎧3x − 2y = −2
2. ⎨
⎩3x + y = 10
⎧ x + y = −7
3. ⎨
⎩x − y = 5
_________________________
________________________
⎧2x − 2y = 14
5. ⎨
⎩ x + 4y = −13
⎧
6. ⎨ y − x = 17
⎩2y + 3x = −11
_________________________
________________________
⎧ 1
⎪⎪− x + y = 4
8. ⎨ 2
⎪ 1 x − y = −3
⎪⎩ 3
⎧3x + y = −15
9. ⎨
⎩2x − 3y = 23
_________________________
________________________
⎧4x − 3y = −9
11. ⎨
⎩5x − y = 8
⎧3x − 3y = −1
12. ⎨
⎩12x − 2y = 16
_________________________
________________________
13. At a bakery, Riley bought 3 bagels and 2 muffins for $7.25.
Karen bought 5 bagels and 4 muffins for $13.25. What is
____________________________________
the cost of each item?
14. A chemist has a beaker of a 3% acid solution and a beaker of
a 7% acid solution. He needs to make 75 mL of a 4% acid solution.
a. Complete the table.
Amount of Solution (mL)
Amount of Acid (mL)
3% solution
+
7% solution
=
4% solution
x
+
y
=
________
+
_____ y
=
0.04(75)
_____
x
b. Use the information in the table to write a system of
linear equations.
_____________________________________
c. Solve the system of equations to find how much he
will use from each beaker.
_________________________________________________________________________________________
Original content Copyright © by Holt McDougal. Additions and changes to the original content are the responsibility of the instructor.
6-21
Holt McDougal Algebra 1
Review for Mastery
LESSON 6–3
Practice A
1. 0y; 3x; 3; 3; 2; 2; 2; 2; 2; 12; 4; 2; 4
2. 2y; −7; 0y; −3; −3; −1; −1; 3; 3; 3; 9; 9; 9;
−2; 2; 2; −1; 3; −1
5. (6, −2)
6. (−8, −1)
7. 3 and −4
2. (4, −1)
3. (−6, 18)
4. (−4, −14)
5. (7, 10)
6. (7, −18)
7. (5, −2)
3. 2; 4; −16; 5; 10; 5; 10; 5; 5; 2; 2; 2; 2; 2;
−10; −2; −2; 5; 2; 5
4. (3, 4)
1. (3, −14)
Challenge
⎧5 x + 4 y + z = 865
1. ⎨
⎩9 x + 6 y + 6z = 1410
2. 5x − 2y = 20
3. −21x − 18y = −3780
Practice B
1. −4y = 24; −6; −2; −2; −6
4. x = 60
2. −6; 2; −34; −2x = −14; 7; −4; 7; −4
⎧2y + z = 285
5. ⎨
⎩4 y + z = 565
3. (2, −3)
4. (−9, 1)
5. (4, −6)
⎛ 1 ⎞
6. ⎜ − , 3 ⎟
⎝ 2 ⎠
7. (−4, −1)
⎛ 1
⎞
8. ⎜ − , −2 ⎟
⎝ 5
⎠
6. y = 140, z = 5
7. sleeping bags: $60; tents: $140;
bug repellant: $5
Problem Solving
9. $22
1. chicken leg 8 oz.,
10. 7 Gala apples; 12 Granny Smith apples
chicken wing 3 oz.
2. bath towel $10,
Practice C
hand towel $5
1. (3, −1)
2. (2, 4)
3. (−1, −6)
⎛ 1 1⎞
4. ⎜ , ⎟
⎝3 4⎠
3. adult ticket $8,
5. (3, −4)
6. (−9, 8)
4. office visit $25,
7. (13, −2)
8. (−6, 1)
9. (−2, −9)
10. (−10, −1)
11. (3, 7)
child ticket $5
allergy shot $8
5. A
⎛5 ⎞
12. ⎜ , 2 ⎟
⎝3 ⎠
6. G
Reading Strategies
1. Multiply the first equation by 3 and the
second equation by 5 to get common
coefficients of −15.
13. bagel: $1.25; muffin: $1.75
14. 75; 0.03; 0.07
⎧4(9 x − 10 y = 7) ⎧36 x − 40 y = 28
⇒⎨
2. ⎨
⎩5(5 x + 8 y = 31)
⎩25 x + 40 y = 155
⎧ x + y = 75
⎨
⎩0.03 x + 0.07 y = 3
3. (1, −3)
56.25 mL of the 3% solution; 18.75 mL
of the 7% solution
4. (10, −10)
Original content Copyright © by Holt McDougal. Additions and changes to the original content are the responsibility of the instructor.
A72
Holt McDougal Algebra 1