1. Solving an order system
2. Let us solve this one by combining the two equations:
2x – y = 7
2y = 4x – 14 --> y = 2x – 7
combine:
2x – (2x – 12) = 7
2x – 2x + 7 = 7
0 + 7 = 7
7 = 7
No variable at the end, therefore infinite solutions
3. From the given equations itself, we can see that this is impossible to have solutions, therefore:
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4. y – x = -1 --> y = x – 1
x + (x – 1) = -5
2x – 1 = -5
x = -2
y = x – 1 = -2 – 1 = -3
(-2, -3)
5. x = y
x + x = 4
2x = 4
x = 2 = y
(2, 2)
1 solution
6. x – y = 2 --> x = 2 + y
3 (2 + y) + 2y = 6
6 + 3y + 2y = 6
5y = 0
y = 0
x = 2 + y = 2
(0, 2)
1 solution
7. 4x + (x + 6) = 1
5x + 6 = 1
5x = -5
x = -1
y = x + 6 = -1 + 6 = 5
(-1, 5)
8. x – y = 5 --> x = 5 + y
2 (5 + y) + y = 1
10 + 2y + y = 1
3y = -9
y = -3
x = 5 + y = 5 – 3 = 2
(2, -3)
1 solution