1/f=4(1/g + 1/H)?

Question

Solve for H! I can't seem to get it....can you also explain HOW you got it...thanks

Answer 1

1/f = 4(1/g + 1/H)

first divide by 4:

1/(4f) = 1/g + 1/H

now subtract 1/g:

1/(4f) - 1/g = 1/H

You need to get a common denominator on the left:

g/(4fg) - (4f)/(4fg) = 1/H
(g-4f)/(4fg) = 1/H

Now that you have a fraction = a fraction, you can cross multiply:

H(g-4f) = 4fg

Now divide both sides by (g-4f):

H = (4fg)/(g-4f)

Answer 2

1/ f = 4 / g + 4 / H

1/ f - 4 / g = 4 / H

(g - 4f) / fg = 4 / H

H / 4 = fg / (g - 4f)

H = 4fg / (g - 4f)