Question 179472
Solve by substitution or elimination method: 
4x-5y=14
-12x+15y=-42 
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Multiply 1st by 3 to get:
12x - 15y = 42
-12x+ 15y = -42
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Important thought: IF you assume the x's and the y's are respectively
the same, you may add the two equations to get:
0 = 0
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Now, 0=0 is a true statement.
So, your assumption was correct; the x's and the y's are respectively the same.
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So x may have any value; then y = (12/15)x - (42/15)
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What does that say about the SYSTEM of two equations?
It says one is the multiple of the other; they are essentially the same.
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Cheers,
Stan H.