Answer:
-7/24
Explanation:
Isolate the variable, r. Note the equal sign, what you do to one side, you do to the other.
Subtract 2/3 from both sides:
3/8 (-2/3) = r + 2/3 (-2/3)
3/8 - 2/3 = r
Simplify. First, find common denominators. Note that what you do to the denominator you do to the numerator.
(3/8) x (3/3) = (9/24)
(2/3) x (8/8) = (16/24)
Subtract:
(9/24) - (16/24) = -7/24
r = -7/24
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