1. Solving Systems Using Substitution
ALGEBRA 1 LESSON 7-2
pages 349–352  Exercises
1. D
2. C
3. B
4. A
5–16. Coordinates given in
alphabetical order.
5. (9, 28)
6. (– , –4 )
7. (6 , – )
8. (2, 4 )
9. (4, 20)
10. ( , 9 )
11. (2, 0)
12. (7 , )
13. (6, –2)
14. (3, –2)
15. (8, –7)
16. (–3, 9.4)
17. 4 cm by 13 cm
18. 4 wk
19. (15, 15)
20. (9, 126)
21. (–4, 4) 3 4 3 8
video rentals
acres flax,
160 acres sunflowers
24. 9 yr
25. estimate: ( , 1); 
; ( , 1) 7 17 8 17 1 2 1 2 1 2 1 2 1 3 1 3 1 2
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2. Solving Systems Using Substitution
ALGEBRA 1 LESSON 7-2
28. estimate: (–3.5, –3.5);
(– , – )
29. estimate: (– , 4 );
(– , )
26. estimate: (–2, 3); 
; (–2, 3)
27. estimate: (–1, 1);
(–1, 1) 10 3 11 3 3 4 3 4 2 3 14 3
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3. Solving Systems Using Substitution
ALGEBRA 1 LESSON 7-2
30. estimate: (–4, 0);
(– , – )
31. a. Let n = number of nickels,
let d = number of dimes.
        n + d = 28
0.05n d = 2.05
b. Solve the first eq. for either var.
Sub. the expression into the second
eq. Solve this eq. for the other var.,
and then sub. its value into the first
eq. and solve for the first var.
c. (15, 13)
32. Answers may vary.
Sample: y = x and y = –3x + 2;
( , )
33. a. (x, y) such that y = 0.5x + 4 b.
c. Graphing shows only one line.
Substitution results in a true
equation with no variables. 1 2 1 2 50 11 2 11
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4. Solving Systems Using Substitution
ALGEBRA 1 LESSON 7-2
38. (2, )
39. (– , 0)
40. (4, –2)
41. inf. many solutions
42. no solution
43. 1 solution
44. a. g = b
b. (b, g) = (572, 598)
c. 26
45. a. (t, d) = (9, 79.2)
b. yes
46. (r, s, t) = (7, 9, 4) 1 2
50. [2] 7(–7) – 4(–2) 29
      –
           –
No, (–2, –7) must
satisfy both
equations to be a
solution of the
system.
[1] no explanation
given
34. a. no solution b.
c. Graphing shows 2 parallel lines. Substitution results in a false equation with no variables.
35. (2, 4)
36. (– , – )
37. (2, –4) 1 2 = / 23 22 1 2 1 2
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5. Solving Systems Using Substitution
ALGEBRA 1 LESSON 7-2
51. (12, 10);
52. (2, 1);
53. (4, 2);
54.
55.
56.
57.
58.
59.
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