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11 votes
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Seven x's and 3y's cost as much as 4z's. One z costs as much as 1x plus 1y together. How many x's cost as much as 1y?

User Doppelganger
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1 Answer

26 votes
26 votes

Answer:

Explanation:

Equations

7x + 3y = 4z

Second equation

x + y = z Multiply the entire equation by 4

4[x + y = z] Now distribute the 4 through the equation

4x + 4y = 4z Both equations = 4z. Equate the lefts.

Third equation

7x+3y = 4x + 4y Subtract 3y from both sides

7x + 3y -3y = 4x + 4y -3y

7x = y + 4x Subtract 4x from both sides

7x - 4x = y + 4x - 4x Combine

3x = y

Answer: 3x = y

User Nahuel Fouilleul
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