Question

Show the steps and solution explanations.

A. x+4y=6
x+4y=15

B. x+4y=7
3x +12y=21

C x-y=1
2x +y=4

Answer 1

Explanation:

x+4y=6

x+4y=15

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x+4y=6

-(x+4y)=-15

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x+4y=6

-x-4y=-15

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0=-9

no solution

Answer: No Solution

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x+4y=7

3x+12y=21

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simplify 3x+12y=21 into x+4y=7

Answer: Infinitely many solutions

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x-y=1

2x+y=4

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x=y+1

2(y+1)+y=4

2y+2+y=4

3y=4-2

3y=2

y=2/3

x-2/3=1

x=1+2/3

x=3/3+2/3=5/3

Answer: x=5/3, y=2/3. (5/3, 2/3).