-2u3y 25x3
------- - --------- =
15xz5 14u2y2
To subtract fractions, you need a common denominator; in this case, the common denominator is found by multiplying both denominators together:
Denominator of each fraction = 15xz5 · 14u2y2 = 210xz5u2y2
So, both the numerator and denominator of the first fraction must be multiplied by 14u2y2
Numerator of the first fraction = -2u3y · 14u2y2 = -28u5y3
And, both the numerator and denominator of the second fraction must be multiplied by 15xz5
Numerator of the second fraction = 25x3 · 15xz5 = 375x4z5
The problem is now: [ -28u5y3 / 210xz5u2y2 ] - [ 375x4z5 / 210xz5u2y2 ]
Combining the two numerators: -28u5y3 - 375x4z5 over the common denominator: 210xz5u2y2 gives you your answer"
= ( -28u5y3 - 375x4z5 ) / 210xz5u2y2