Question

If x+y=9 and xy=20, find x-y

Answer 1

Step-by-step explanation:

x+y=9

so, (x+y)²=9²

x²+y²+2xy=81

x²+y²+2×20=81

x²+y²=81-40

x²+y²=41............(I)

(x-y)²=x²+y²-2xy

(x-y)²=41-2xy(using equ (I)

(x-y)²=41-40

(x-y)²=1

x-y=√1

x-y=1

hope it help you!!!

Answer 2

☆Given :

• x + y = 9

• xy = 20

☆To find :

• x - y

✒ Solution :

$\bigstar$ Suppose the value of :

• x = 5

• y = 4

$\bigstar$ Check

1) x + y = 9

$\: \: \: \: \: \implies$5 + 4 = 9

$\bigstar$ 9 = 9

L.H.S = R.H.S

Hence proved

2) xy = 20

$\: \: \: \: \: \implies$ 5 × 4 = 20

$\bigstar$ 20 = 20

L.H.S = R.H.S

Hence proved

3) x - y = ?

$\: \: \: \: \: \implies$ 5 - 4 = ?

$\bigstar$ = 1

$\therefore$ value of x - y = 1