Answer:
In your original answer, you did not distribute the 7 to the 3j
Explanation:
The distributive property basically states that the sum of any variables multiplied by a factor is equal to the sum of each product of every individual variable and the factor.
In short,
a(b+c) = ab + ac
or
x(y + w + z) = xy + xw + xz
or
9m + 9n = 9 (m+n)
Therefore, in order to solve 7(3j + 10)
you must multiply 7 by 3j and 7 by 10
(7 * 3j) + (7 * 10) = 21j + 70
Since 70 does not have the same terms as 21j (70 does not have j),
21j + 70 is in its most simplified form.
In your original answer, you didn't multiply the 3j by 7.