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Solve 3x + 4y = 9 and x - 2y = -7 using substitution

User Stu Gla
by
5.3k points

2 Answers

12 votes

Answer: x=−1 and y=3

Step-by-step explanation: 3x+4y=9, x−2y=−7

x−2y=−7, 3x+4y=9

x−2y=−7

x−2y+2y=−7+2y

x=2y−7

3x+4y=9

3(2y−7)+4y=9

10y−21+21=9+21

10y /10 = 30 /10

y=3

x=2y−7

x=(2)(3)−7

x=−1

x=−1 and y=3

User Bruno Grieder
by
4.4k points
11 votes

Answer:

x = -1

y = 3

Explanation:

Please let me know if you want me to add an explanation as to why this is the answer. I can definitely do that, I just wouldn’t want to write it if you don’t want me to :)

User Dmitry Velychko
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5.2k points