Question

cứu vs

 

Answer 1

2:

a: A=(x-1)(x+3)

=x^2+3x-x-3

=x^2+2x-3

=x^2+2x+1-4

=(x+1)^2-4>=-4

Dấu = xảy ra khi x=-1

b: B=(x-2)(x+5)

=x^2+5x-2x-10

=x^2+3x-10

=x^2+3x+9/4-49/4

=(x+3/2)^2-49/4>=-49/4

Dấu = xảy ra khi x=-3/2

c: C=(x+2)(x+3)

=x^2+5x+6

=x^2+5x+25/4-1/4

=(x+5/2)^2-1/4>=-1/4

Dấu = xảy ra khi x=-5/2

d: D=(x-2)(x-4)

=x^2-6x+8

=x^2-6x+9-1

=(x-3)^2-1>=-1

Dấu = xảy ra khi x=3

e: E=(x+3)(x-2)

=x^2-2x+3x-6

=x^2+x-6

=x^2+x+1/4-25/4

=(x+1/2)^2-25/4>=-25/4

Dấu = xảy ra khi x=-1/2

g: G=(x+1)(x+5)

=(x+3-2)(x+3+2)

=(x+3)^2-4>=-4

Dấu = xảy ra khi x=-3