SOLUTION: Can the system 4x + 5y = -4 12x - 9y = -4 be solved more easily by using the substitution method or the addition method? And why?

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Question 144833: Can the system
4x + 5y = -4
12x - 9y = -4
be solved more easily by using the substitution method or the addition method? And why?

Answer by solver91311(24713) About Me  (Show Source):
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Solving either of the equations for either of the variables will result in a messy fraction that must then be substituted in order to solve by the substitution method. Multiplying the first equation by a nice, neat -3 allows elimination of the x variable, hence the addition method (more properly termed the elimination method) is the easier process for this system.