The error that Barbara's made is that Barbara wrote (d+63) instead of (d+9).
<h3>What is Distributive property?</h3>The distributive property of multiplication is that when two numbers are added such as (a+b) and multiplied by a third number such as x, then the result will be the sum of multiplication of the third number with the first number (xa) and the third number with the second number (xb).
x(a+b) = xa + xb,
The expression which is equal to the expression 7d+63 can be written as,
Hence, the error that Barbara's made is that Barbara wrote (d+63) instead of (d+9).
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