## ROBERT3 2 years ago Find the lowest common denominator for the set of fractions. 7/x^2+4x+4 5/4-x^2

1. ROBERT3

2. ROBERT3

@matricked

3. matricked

the reqd LCM is 35/(x+2)

4. matricked

lcm of fraction is lcm of numerator /hcf of denominator thus lcm of 7 and 5 here is 35 and hcf of (x+2)^2 and (2+x)(2-x) is (x+2) hence the result

5. ROBERT3

@satellite73

6. ROBERT3

The denominator for the first one factors out to (x+2)(x+2). You get this by taking the coefficient of "4" and finding mult's that if adding together would give you the middle x term which is +4, then you would have x^2+2x+2x+4, you would use factor by grouping,(x^2+2x)(2x+4). Pull out the x from the first group, than a 2 from the second group. This will leave you with (x+2)(x+2). Now, the second part is "perfect squares," it is simply (2-x)(2+x). Now, with both of those done you come up with the final answer: (x+2)(2-x)is you LCD. If you are asking why not the (2+x), it is because that one is exact same as the (x+2), just written different but still the same value.

7. ROBERT3

@amir.sat

8. amir.sat

@ROBERT3 u r right we should multiply both side by (x+2)(2-x) after that we have a equation to solve

9. ROBERT3

in my answer is 2x+(x+2) is correct @amir.sat

10. ROBERT3

i need help @ajprincess

11. ajprincess

|dw:1352817765723:dw|

12. ajprincess

getting it @robert3?