Question

Calcule:

1- x² - xy, sendo x= 2/5 e y= -1/10

2- -x² - 6x, sendo x= -2/3

3- 2x² - 5x - 3, sendo x= -1/2

Answer 1

1-x^2-xy=
1-(2/5)^2-2/5.-1/10=
1-4/25+2/50=
50/50-8/50+2/50=
42/50+2/50=
44/50=
22/25

2-x^2-6x
2-(-2/3)^2-6(-2/3)=
2-4/9+12/3=
18/9-4/9+36/9=
14/9+36/9=
50/9

3-2x^2-5x-3
3-2(-1/2)^2-5(-1/2)-3=
3-2(1/4)+5/2-3=
3-2/4+5/2-3=
12/4-2/4+10/4-12/4=
10/4+10/4-12/4=
20/4-12/4=
8/4=
2