Question

x+y=9
x-y=5

x×y=?

Multumesc din avans

Answer 1

x=9-y => pe x il inlocuiesti in cealalta ecuatie =>
9-y-y=5 => 9-2y =5 => -2y=-4 => y=2
x=9-2 => x=7 => x×y=2×7 => x×y=14

sper ca te-am ajutat :)

Answer 2

x+y=9

x-y=5

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2x = 9+5

2x = 14

x = 14 : 2

x = 7

7 - y = 5

y = 7 - 5

y = 2

x × y = 7 × 2 = 14