Question

(Ulbra-RS) sendo A=x-3, B=x²+3 e C=9x,0 valor de A²- b+c é?

Answer 1

A = X - 3
B = X² + 3
C =9X

A² - B + C  =
( X - 3)² - ( X² + 3) +9X=
( X² - 2 . 3 . X  + 3² ) - X² - 3 +9X =
X² - 6X + 9 - X² - 3 + 9X =
3X  + 6 = 
3 ( X + 2 )  RESPOSTA  ***

Answer 2

Se C for =9x
(x-3)²-(x²+3)+(9x)=0
X²-3x-3+9-x²-3+9x=0
Arrumando
6x-9x+6=0
-3x=6
X=-2