M - n m = 300x + 100, so we substitute that into the equation for m. 300x + 100 - n n = 250x + 200, so we substitute that into the equation for n. 300x + 100 - 250x - 200 Subtract the 250x to get: 50x + 100 - 200 Subtract the 200 to get: 50x - 100, which is option D. Hope this helps!
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