What is the slope-intercept form of the equation of the line that passes through the points (2, 7) and (4, −1)?

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Jackie purchased 3 bottles of water and 2 cups of coffee for the family for $7.35. ryan bought 4 bottles of water and 1 cup of coffee for his family for 7.15. how much does each bottle of water cost? how much does each cup of coffee cost?

Which representation has a constant of variation of -2.5