Question

me ajudem por favor !!!!!!!!!!!
a) (-5x + 4y - 6z) + (+ 6x - 8y - 12z)=
b) 18b-(-32c + 13b - 6d) + 5b + 21c=
c) (x + 9). (x - 9)=

Answer 1

a)
(-5x+4y-6z)+(6x-8y-12z)=
-5x+4y-6z+6x-8y-12z=
-5x+6x+4y-8y-6z-12z=
x-4y-18z

b)
18b-(-32c+13b-6d)+5b+21c=
18b+32c-13b+6d+5b+21c=
18b-13b+5b+32c+21c+6d=
23b-13b+53c+6d=
10b+53c+6d

c)
(x+9)(x-9)=
x²-9x+9x-81=
x²-81