SOLUTION: I have 3 questions: 1) I= nE/(nr+R) (solve for n) 2) 1/a + 1/b = c (solve for a). I think the LCD is ab. To isolate a, I need to divide both sides by bc. Then I get lost

Algebra ->  Linear-equations -> SOLUTION: I have 3 questions: 1) I= nE/(nr+R) (solve for n) 2) 1/a + 1/b = c (solve for a). I think the LCD is ab. To isolate a, I need to divide both sides by bc. Then I get lost      Log On


   

Question 443781: I have 3 questions:
1) I= nE/(nr+R) (solve for n)
2) 1/a + 1/b = c (solve for a). I think the LCD is ab.
To isolate a, I need to divide both sides by bc. Then I get lost!
3) Using the quadratic formula, solve 5x^2+8x+2=0. a=5, b=8, c=2; plug them into the quadratic formula -b plus or minus the square root of(b^2-4ac)divided by 2a.
I am having a hard time with the steps for the answer because I looked up the answer but can't seem to figure the steps correctly. I beleive the answer to be (-4 plus or minus the square root of 6)divided by 5. But I keep coming up with (-8 plus or minus the square root of 24)divided by 10.
I would really appreciate your help! Thanks so much.
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
2) 1/a + 1/b = c Solve for a
b+a=abc Multiply each side by ab.
a-abc=-b
a(1-bc)=-b
a=-b/-(bc-1)
a=b/(bc-1)
.
Ed