Final answer:
An equation in the slope-intercept form that represents the relationship between the number of letters engraved on a water bottle and its total cost would be 'Total cost = 18.99 + 1.35(number of letters)'. This assumes a fixed cost of 18.99 for the bottle and an additional cost of 1.35 per engraved letter.
Step-by-step explanation:
The subject of the question is mathematics and it's about creating an equation in the slope-intercept form to represent the relationship between two variables – the number of letters to be engraved on the water bottle and the total cost of the water bottle. According to the information given: the set price for a water bottle is a fixed cost (which in the context of slope-intercept form of an equation is the y-intercept) and the additional fee per letter is a variable cost (which is the slope).
Referring to the slope-intercept form y = a + bx, where: y is the total cost, a is the fixed cost (y-intercept), b is the cost per letter (slope), and x is the number of letters. The correct equation, based on the information provided, would be: Total cost = 18.99 + 1.35(number of letters).
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