2/(y-5) = 3/(y+6)
S soroban Elite Member Joined Jan 28, 2005 Messages 5,586 Jul 8, 2007 #2 Re: Math help please Hello, baxleyad! \(\displaystyle \L\frac{2}{y\,-\,5}\; = \;\frac{3}{y\,+\,6}\) Click to expand... Multiply both sides by \(\displaystyle (y\,-\,5)(y\,+\,6):\) . . \(\displaystyle (y\,-\,5)(y\,+\,6)\,\cdot\,\frac{2}{y\,-\,5} \;=\;(y\,-\,5)(y\,+\,6)\,\cdot\,\frac{3}{y\,+\,6}\) . . \(\displaystyle 2(y\,+\,6) \;=\;3(y\,-\,5)\) . . \(\displaystyle 2y\,+\,12\;=\;3y\,-\,15\) . . \(\displaystyle 2y\,-\,3y \;=\;-15\,-\,12\) . . . . \(\displaystyle \,-y \;=\;-27\) . . . . . . \(\displaystyle y \;=\;27\)
Re: Math help please Hello, baxleyad! \(\displaystyle \L\frac{2}{y\,-\,5}\; = \;\frac{3}{y\,+\,6}\) Click to expand... Multiply both sides by \(\displaystyle (y\,-\,5)(y\,+\,6):\) . . \(\displaystyle (y\,-\,5)(y\,+\,6)\,\cdot\,\frac{2}{y\,-\,5} \;=\;(y\,-\,5)(y\,+\,6)\,\cdot\,\frac{3}{y\,+\,6}\) . . \(\displaystyle 2(y\,+\,6) \;=\;3(y\,-\,5)\) . . \(\displaystyle 2y\,+\,12\;=\;3y\,-\,15\) . . \(\displaystyle 2y\,-\,3y \;=\;-15\,-\,12\) . . . . \(\displaystyle \,-y \;=\;-27\) . . . . . . \(\displaystyle y \;=\;27\)
D Denis Senior Member Joined Feb 17, 2004 Messages 1,707 Jul 8, 2007 #3 Cross multiplication is also a way; remember that if a/b = c/d, then ad = bc 2 / (y-5) = 3 / (y+6) 2(y+6) = 3(y-5) 2y + 12 = 3y - 15 3y - 2y = 12 + 15 y = 27
Cross multiplication is also a way; remember that if a/b = c/d, then ad = bc 2 / (y-5) = 3 / (y+6) 2(y+6) = 3(y-5) 2y + 12 = 3y - 15 3y - 2y = 12 + 15 y = 27
