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3. Use the SUBSTITUTION method to solve this system of equations: 2x+y=12, 7x-4y=12

2 Answers

4 votes

Answer:

x = 4 , y = 4

Explanation:

given the system of equations

2x + y = 12 ( subtract 2x from both sides )

y = 12 - 2x → (1)

7x - 4y = 12 → (2)

substitute y = 12 - 2x into (2)

7x - 4(12 - 2x) = 12 ← distribute parenthesis on left side and simplify

7x - 48 + 8x = 12

15x - 48 = 12 ( add 48 to both sides )

15x = 60 ( divide both sides by 15 )

x = 4

substitute x = 4 into (1) and solve for y

y = 12 - 2(4) = 12 - 8 = 4

the solution is x = 4 , y = 4

User Ylisar
by
7.2k points
4 votes

Answer:

7x - 4(12 - 2x) = 12

7x - 48 + 8x = 12

15x = 60

x = 4, y = 4

User Incrop
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7.9k points