4/5 - 8/7 cannot be subtracted since they don't have the same denominator.
But you can achieve the difference by getting the LCD and to get the LCD you must Determine the Greatest Common Factor of 4 and 8 which is 2, then Either multiply the numbers and divide by the GCF (4*8=32 and 32/2=16) or Divide one of the numbers by the GCF and multiply the answer times the other number (4/2=2 and 2*8=16), then rename or transform the fractions using the LCD as the denominator(4/5=4/16 and 8/7=8/16). Now we can subtract the fractions. 4/16-8/16=4/16 or 1/4
12/35 is my answer
Since 8/7 and 4/5 are not the same denominator you should get the LCD which is 35. so the answer 12/35