Question

Simplify $3x(4x-5)+3$ and find its values for $x=\frac{1}{2}$.

• A. $\frac{3}{2}$
• B. $-\frac{9}{2}$
  
• C. $-\frac{3}{2}$
• D. $\frac{9}{2}$

Answer 1

Answer: (C)

$-\frac{3}{2}$

$3x(4x-5)+3$
$=12x^2-15x+3$
Putting the value of $x$ we get,
$12(\frac{1}{2}{)}^2-15(\frac{1}{2})+3$
$=12\times \frac{1}{4}-15\frac{1}{2}+3$
$=3-\frac{15}{2}+3$
$=\frac{6-15+6}{2}$
$=-\frac{3}{2}$