Piper claims that 3(2a + 2) is equivalent to 5a + 6. she checks her claim by substituting -3 for a. is piper's claim correct? why or why not?

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How can you tell when x and y are not directly proportional?

Shannon drove for 540 minutes. if she traveled 65 miles per hour,how many total miles did she travel?

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )