- #1
thomas49th
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Homework Statement
(a) [tex]\frac{3}{x}+\frac{3}{2x} = 2 [/tex]
that is 4x = 9 so x = 2.25
(b) I can do the first question (a) easy peasy , however the secnond question says "using your answer to part (a), or otherwise solve:
[tex]\frac{3}{(y-1)^{2}}+\frac{3}{2(y-1)^{2}} = 2[/tex]
What part of (a) do I use to solve part (b)
The Attempt at a Solution
for (b)
1) Expand (y-1)² = y² - 2y + 1
2) Expand 2(y-1)² = 2(y² - 2y + 1 ) = 2y² - 4y + 2
3) Double 1'st fraction to get equal denominators then add fractions
[tex]\frac{6}{2y^{2} - 4y + 2}[/tex]
4) Crossmultiply so you get [tex]3 = 4y^{2} - 8y + 4[/tex]
then complete the square
(4y - 4)² - 16 + 4 = 3
y = [tex]\frac{4 +- \sqrt{15}}{4}[/tex]
but that GETS a bit complicated for NON CALCULATOR level so i tried using the formula which gave me y = 1 or 1 (when at the bottom of the question there is 2 answers). Have I made a mistake in my calculations, and what about using part (a) to help answer part (b), I havn't done that, how do they link in together?
Thx