Question

${x}^{2} - {y}^{2} = 63$
si
$x - y = 7$

Answer 1

X ² - Y² =63⇒ (X - Y) (X +Y) =63

X -Y = 7

(X - Y) (X +Y) =63 DAR X - Y =7 DECI X+Y =63:7

DECI X+Y =9

DAR X + Y = 9

X - Y = 7

SE ADUNA CELE 2 ECUATII

2X =9 + 7⇒ 2X =16 ⇒ X = 8

8 - Y =7 ⇒ Y =8 -7 =1

DECI X = 8 SI Y = 1

Answer 2

x² - y² = 63

( x - y ) ( x + y ) = 63

7 ( x + y ) = 63

x + y = 63 : 7

x + y = 9

x - y = 7⇒ x = y + 7

y + 7 + y = 9

2 y = 9 - 7

y = 1

x = 8

Verific: 8² - 1² = 64 - 1 = 63