Question

Помогите пожалуйста...​

Answer 1

1:

(3x-4)²+(2x-4)(2x+4)+65x

9x²-24x+16+65x+(2x-4)(2x+4)

9x²+41x+16+4x²-16

13x²+41x

При x = -3:

13*9-41*3=-6

Ответ: -6

2:

$\left \{ {{x^{2}-y^{2}=64} \atop {x-y=2}} \right. \\\left \{ {{(2+y)^{2}-y^{2}=64} \atop {x=2+y}} \right. \\\left \{ {{4+4y+y^{2}-y^{2}=64} \atop {x=2+y}} \right. \\\left \{ {{4y=60} \atop {x=2+y}} \right.\\\left \{ {{y=60/4=15} \atop {x=2+y=2+15=17}} \right.$

Ответ: x = 17, y = 15

3.

$\left \{ {{x^{2}-y^{2}=25} \atop {x+y=25}} \right. \\\left \{ {{(25-y)^{2}-y^{2}=25} \atop {x=25-y}} \right.\\\left \{ {{625-50y+y^{2}-y^{2}=25} \atop {x=25-y}} \right.\\\left \{ {{625-50y=25} \atop {x=25-y}} \right.\\\left \{ {{50y=600} \atop {x=25-y}} \right.\\\left \{ {{y=600/50=12} \atop {x=25-y=25-12=13}} \right.$

Ответ: x = 13, y = 12