Answer:
5 marbles are black.
Step-by-step explanation:
7-2=5
Answer:
m = 25/28
Step-by-step explanation:
It's best to enclose fractional coefficients inside parentheses to eliminate ambiquity: 2/7m-1/7=3/14 => (2/7(m - (1/7) = (3/14).
The LCD is 14; each of the denominators {7, 14} divides evenly into 14. Hence our equation becomes
(4)(m - 1/7) = 3
... after multiplying every term by 14.
Let's multiply each side by 7 to eliminate the remaining fraction:
4(7m - 1) = 21, or
28m - 4 = 21, or
28m = 25.
Hence, m = 25/28.
