Answer:
-1/60
Explanation:
The fractions have unlike denominators. First, find the Least Common Denominator and rewrite the fractions with the common denominator.
LCD(9/20, 7/15) = 60
Multiply both the numerator and denominator of each fraction by the number that makes its denominator equal the LCD. This is basically multiplying each fraction by 1.
(9/20×33)−(7/15×44)
Complete the multiplication and the equation becomes
27/60−28/60
The two fractions now have like denominators so you can subtract the numerators.
Then:
27−28/60=−1/60
This fraction cannot be reduced.
Therefore:
9/20−7/15=−1/60