Answer:
1/21
Explanation:
Changing operations to eliminate negative numerators the equation becomes
=1/3−2/7
With unlike denominators find the Least Common Denominator (LCD)
LCD = 21
Multiplying numerators and denominators to get the LCD in all fraction denominators
=1×7/3×7 −2×3 /7×3
Then rewriting the equation with the equivalent fractions
=7/21−6/21
With like denominators we can operate on just the numerators
=7−6/21
=1/21