If both $x-2$ and $x-\frac{1}{2}$ are factors of $p x^{2}+5 x+r,$ show that $p=r$
Let $p(x)=p x^{2}+5 x+r$
As $(x-2)$ is a factor of $p(x)$
So, $p(2)=0 \Rightarrow P(2)^{2}+5(2)+r=0$
$\Rightarrow \quad 4 p+10+r=0.....(1)$
Again, $\left(x-\frac{1}{2}\right)$ is factor of $p(x)$
$\therefore \quad p\left(\frac{1}{2}\right)=0$
Now, $\quad p\left(\frac{1}{2}\right)=p\left(\frac{1}{2}\right)^{2}+5\left(\frac{1}{2}\right)+r$
$=\frac{1}{4} p+\frac{5}{2}+r$
$\therefore \quad p\left(\frac{1}{2}\right)=0 \Rightarrow \frac{1}{4} p+\frac{5}{2}+r=0....(2)$
From $(1),$ we have $4 p+r=-10$
From $(2),$ we have $p+10+4 r=0$
$\Rightarrow \quad p+4 r=-10$
$\therefore \quad 4 p+r=p+4 r$ $[\because$ Each $=-10]$
$\therefore \quad 3 p=3 r \Rightarrow p=r$
Hence, proved.
If $(2 x+3)(3 x-1)=6 x^{2}+k x-3,$ then find $k$.
Factorise
$16 x^{2}-16 x-21$
Expand
$\left(\frac{x}{2}-\frac{2}{5}\right)^{2}$
Evaluate $66 \times 74$ without directly multiplying
Find $p(1), p(2)$ and $p(4)$ for each of the following polynomials
$p(y)=y^{2}-5 y+4$