Question

Solve for $y:$ $2y^2+4=9y$

• A. $\{2,4\}$
• B. $\{\frac{1}{2},2\}$
• C. $\{2,2\}$
• D. $\{\frac{1}{2},4\}$

Answer 1

Answer: (D)

$\{\frac{1}{2},4\}$

Given, $2y^2+4=9y$
$\Rightarrow 2y^2-9y+4=0$
Comparing it with standard form quadratic equation $a{x}^2+bx+c=0$, we get,

$a=2,b=-9,c=4$
Thus required roots are $y=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$
$y=\frac{9\pm \sqrt{81-32}}{4}=\frac{9\pm 7}{4}=4,\frac{1}{2}$
Hence, correct choice is option D.