Question

x+y=7 and x-y=3, x2-y2=

Answer 1

X^2 - Y^2 =(X+Y) (X-Y) =7*3=21

HOPE IT HELPS YA

Answer 2

$given \: that \: \\ \\ x + y = 7.....(1) \\ \\ and \: \\ x - y = 3......(2) \\ \\ from \: equation \: (1) \\ \\ x + y = 7 \\ \\ = > x = 7 - y \\ \\ putting \: this \: value \: of \: x \: in \: equation \: (2) \\ \\ 7 - y - y = 3 \\ \\ = > - 2y = 3 - 7 \\ \\ = > - 2y = - 4 \\ \\ = > y = \frac{ - 4}{ - 2} \\ \\ = > y = 2 \\ \\ putting \: this \: value \: of \: y \: in \: equation \: (1) \\ \\ x + 2 = 7 \\ \\ = > x = 7 - 2 \\ \\ = > x = 5 \\ \\ therefore \\ \\ x = 5 \: \: and \: y = 2 \\ \\ therefore \\ \\ x {}^{2} - y {}^{2} \\ \\ = 5 {}^{2} - 2 {}^{2} \\ \\ = 25 - 4 \\ \\ = 21 \\ \\ \\ hope \: it \: helps.....$