Question

x+y=7/2 and xy=5/2;find:
(i)x-y
(ii)x^2-y^2

Answer 1

Step-by-step explanation:

(i) x - y

${(x - y)}^{2} = {(x + y)}^{2} - 4xy$

$= {( \frac{7}{2}) }^{2} - 4 \times \frac{5}{2}$

$= \frac{49}{4} - 10$

$= \frac{9}{4}$

$= > x - y = \frac{3}{2}$

(ii)

${x}^{2} - {y}^{2} = (x + y)(x - y)$

$= \frac{7}{2} \times \frac{3}{2}$

$= \frac{21}{4}$