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Find the quadratic equation whose roots are \(\frac{2}{3} an...

Find the quadratic equation whose roots are \(\frac{2}{3} and \frac{- 3}{4}\)

A.

\(12y^2 - y - 6 = 0\)

B.

\(12y^2 - y + 6 = 0\)

C.

\(12y^2 + y - 6 = 0\)

D.

\(y^2 + y - 6 = 0\)

Correct answer is C

Let p = \(\frac{2}{3}\) and q =  \(\frac{- 3}{4}\)

using (y - p)(y - q) = 0

= ( y -  \(\frac{2}{3})\)( y - (\(\frac{- 3}{4})) = 0\)

 =  (\( y -  \frac{2}{3})( y + \frac{3}{4})\) = 0

\( y^2 + \frac{3}{4}y - \frac{2}{3}y - \frac{6}{12} = 0 \)

\( y^2 + \frac{1}{12}y - \frac{1}{2}\) = 0

= multiply through by the l. c. m of 3 and 4 = 12

∴ the quadratic equation is  \(12y^2 + y - 6 = 0\)