Question

$x-y=2$ এবং $xy=24$ হলে, $x$ এর ধনাত্মক মানটি কত?

Options :

• (A) $3$
• (B) $4$
• (C) $5$
• (D) $6$

Answer 1

Given,
$x-y=2$ ----- (i)
$xy=24$

We know,
$\left(x+y\right)^2=\left(x-y\right)^2+4xy$

বা, $\left(x+y\right)=\sqrt{\left(x-y\right)^2+4xy}$

বা, $\left(x+y\right)=\sqrt{2^2+4\times24}$

বা, $\left(x+y\right)=\sqrt{100}$

বা, $\left(x+y\right)=10$  ----- (ii)

(ii) + (i)
$\left(x+y\right) + \left(x-y\right) = 10+2$

বা, $x+\cancel y+x-\cancel y=12$

বা, $2x=12$

বা, $x=\frac{12}{2}$

$\therefore x=6$