Answer:
(4 (x^4 - 20 x^2 - 12))/(3 x^2 (9 x^2 - 32 x - 144))
Step-by-step explanation:
Simplify the following:
(x^2 + x - x - 20 - 12/x^2)/((15 x^2)/4 + 3 x^2 - 24 x - 60 - 48)
Hint: | Put the fractions in x^2 + x - x - 20 - 12/x^2 over a common denominator.
Put each term in x^2 + x - x - 20 - 12/x^2 over the common denominator x^2: x^2 + x - x - 20 - 12/x^2 = x^4/x^2 + x^3/x^2 - x^3/x^2 - (20 x^2)/x^2 - 12/x^2:
(x^4/x^2 + x^3/x^2 - x^3/x^2 - (20 x^2)/x^2 - 12/x^2)/((45 x^2)/12 + 3 x^2 - 24 x - 60 - 48)
Hint: | Combine x^4/x^2 + x^3/x^2 - x^3/x^2 - (20 x^2)/x^2 - 12/x^2 into a single fraction.
x^4/x^2 + x^3/x^2 - x^3/x^2 - (20 x^2)/x^2 - 12/x^2 = (x^4 + x^3 - x^3 - 20 x^2 - 12)/x^2:
((x^4 + x^3 - x^3 - 20 x^2 - 12)/x^2)/((45 x^2)/12 + 3 x^2 - 24 x - 60 - 48)
Hint: | Group like terms in x^4 + x^3 - x^3 - 20 x^2 - 12.
Grouping like terms, x^4 + x^3 - x^3 - 20 x^2 - 12 = x^4 - 20 x^2 - 12 + (x^3 - x^3):
(x^4 - 20 x^2 - 12 + (x^3 - x^3))/(x^2 ((45 x^2)/12 + 3 x^2 - 24 x - 60 - 48))
Hint: | Look for the difference of two identical terms.
x^3 - x^3 = 0:
((x^4 - 20 x^2 - 12)/x^2)/((45 x^2)/12 + 3 x^2 - 24 x - 60 - 48)
Hint: | In (45 x^2)/12, the numbers 45 in the numerator and 12 in the denominator have gcd greater than one.
The gcd of 45 and 12 is 3, so (45 x^2)/12 = ((3×15) x^2)/(3×4) = 3/3×(15 x^2)/4 = (15 x^2)/4:
(x^4 - 20 x^2 - 12)/(x^2 (15 x^2/4 + 3 x^2 - 24 x - 60 - 48))
Hint: | Put the fractions in (15 x^2)/4 + 3 x^2 - 24 x - 60 - 48 over a common denominator.
Put each term in (15 x^2)/4 + 3 x^2 - 24 x - 60 - 48 over the common denominator 4: (15 x^2)/4 + 3 x^2 - 24 x - 60 - 48 = (15 x^2)/4 + (12 x^2)/4 - (96 x)/4 - 240/4 - 192/4:
(x^4 - 20 x^2 - 12)/(x^2 (15 x^2)/4 + (12 x^2)/4 - (96 x)/4 - 240/4 - 192/4)
Hint: | Combine (15 x^2)/4 + (12 x^2)/4 - (96 x)/4 - 240/4 - 192/4 into a single fraction.
(15 x^2)/4 + (12 x^2)/4 - (96 x)/4 - 240/4 - 192/4 = (15 x^2 + 12 x^2 - 96 x - 240 - 192)/4:
(x^4 - 20 x^2 - 12)/(x^2 (15 x^2 + 12 x^2 - 96 x - 240 - 192)/4)
Hint: | Group like terms in 15 x^2 + 12 x^2 - 96 x - 240 - 192.
Grouping like terms, 15 x^2 + 12 x^2 - 96 x - 240 - 192 = (12 x^2 + 15 x^2) - 96 x + (-192 - 240):
(x^4 - 20 x^2 - 12)/(x^2 ((12 x^2 + 15 x^2) - 96 x + (-192 - 240))/4)
Hint: | Add like terms in 12 x^2 + 15 x^2.
12 x^2 + 15 x^2 = 27 x^2:
(x^4 - 20 x^2 - 12)/(x^2 (27 x^2 - 96 x + (-192 - 240))/4)
Hint: | Evaluate -192 - 240.
-192 - 240 = -432:
(x^4 - 20 x^2 - 12)/(x^2 (27 x^2 - 96 x + -432)/4)
Hint: | Factor out the greatest common divisor of the coefficients of 27 x^2 - 96 x - 432.
Factor 3 out of 27 x^2 - 96 x - 432:
(x^4 - 20 x^2 - 12)/(x^2 (3 (9 x^2 - 32 x - 144))/4)
Hint: | Write ((x^4 - 20 x^2 - 12)/x^2)/((3 (9 x^2 - 32 x - 144))/4) as a single fraction.
Multiply the numerator by the reciprocal of the denominator, ((x^4 - 20 x^2 - 12)/x^2)/((3 (9 x^2 - 32 x - 144))/4) = (x^4 - 20 x^2 - 12)/x^2×4/(3 (9 x^2 - 32 x - 144)):
Answer: (4 (x^4 - 20 x^2 - 12))/(3 x^2 (9 x^2 - 32 x - 144))