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Write a corresponding real world problem to represent 2x - 125=400

Aright triangle has an area of 21 m2. the dimensions of the triangle are increased by a scale factor of 4. what is the area of the new triangle

Charlie is at an amusement park that has 18 different rides. each ride costs $1.75. the function c(r) = 1.75r represents the total amount of money that charlie will spend if he goes on r rides, but he never goes on the same one more than once. what domain and range are reasonable for the function?