Question

por favor ayúdenme!!

Answer 1

RESOLUCIÓN:

Primero aplicamos un producto notable:

BINOMIO AL CUADRADO

$(x + y) {}^{2} = {x}^{2} + {y}^{2} + 2xy \\ (5) {}^{2} = {x}^{2} + {y}^{2} + 2(2) \\ 25 = {x}^{2} + {y}^{2} + 4 \\ 25 - 4 = {x}^{2} + {y}^{2} \\ 21 = {x}^{2} + {y}^{2}$

$(x - y) {}^{2} = {x}^{2} + {y}^{2} - 2xy \\ (x - y) {}^{2} = 21 - 2(2) \\ (x - y) {}^{2} = 21 - 4 \\ (x - y) {}^{2} = 17 \\ x - y = \sqrt{17}$

Ahora resolvemos lo que nos pide:

$T = {x}^{2} + {y}^{2} + x - y - \sqrt{17} \\ T = 21 + \sqrt{17} - \sqrt{17} \\ T = 21$

RESPUESTA:

d) 21