Question

Calcule:

a) ( X+2)²

b) ( X – 3)²

c) ( x-5) (x+5)

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Answer 1

Resposta:

a) (x + 2)²

(x)² + 2.(x)(2) + (2)²

x² + 4x + 4

b)(x+3).(x+3)

x.x= x²

x.3= 3x

3.x= 3x

3.3=9

x²+3x+3x+9 =

x²+6x+9=0

a= 1  b= 6  x=9

delta= b² +4.a.c

delta= 6²+4.1.9

delta= 36+36

delta = 72

x' = -(b) +  / 2.a

x'= - 6 + 6 /2.1

x' = -3 + 6

x" = -(b) -  / 2.a

x" = -6 -6 / 2

x' = -3 -6

c) (x+5).(x-5)=

x^2-5x+5x-25

x^2-25