Answer:
a) the distributive property
b) Yes
Explanation:
a) The distributive property of multiplication over addition tells you ...
a(b+c) = ab +ac
James has a=3, b=8, c=7, so he can fill in the values to get ...
3(8+7) = 3·8 +3·7
Taking this one step into the evaluation, James gets ...
3(3+7) = 3·8 +3·7 = 24 +21 . . . . . . the result James reports
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b) Our result agrees with James' result, so we agree with James.