Answer:
68/495
Explanation:
To evaluate the expression (2a−1/3)÷b/15 when a=−2/5 and b=−8.25, we can substitute the given values of a and b into the expression.
First, let's substitute a with −2/5 and b with −8.25: (2(−2/5)−1/3)÷(−8.25)/15 Next, let's simplify the expression inside the parentheses:
((-4/5)−1/3)÷(−8.25)/15 To simplify the expression further, we need to find a common denominator for 5 and 3. The common denominator for 5 and 3 is 15: ((-4/5)×3/3−1/3)÷(−8.25)/15 =(-12/15−1/3)÷(−8.25)/15=(-12/15−5/15)÷(−8.25)/15
Now, let's simplify the expression inside the parentheses: (-17/15)÷(−8.25)/15 To divide by a fraction, we can multiply by its reciprocal. So, let's multiply by the reciprocal of (−8.25)/15: =(-17/15)×(15/(−8.25))
The 15's cancel out: =(-17/15)×(1/(−8.25/1)) =(-17/15)×(1/(−33/4))
To multiply fractions, we multiply the numerators together and the denominators together: =(-17/15)×(4/−33) =(-17×4)/(15×−33) =(-68)/(-495)
When dividing two negative numbers, the result is positive: =68/495
Therefore, the expression (2a−1/3)÷b/15 when a=−2/5 and b=−8.25 evaluates to 68/495.