Minimum Value of A - B

[nycmathguy]

David Cohen

Seeking steps and/or hint(s) to get me started.

Question:

Must I replace A with 3x^2 + 4x - 5 and B with
x^2 - 4x - 1 as step 1?

 

[MathLover1]

functions
A =3x^2+4x-5
B=x^2-4x-1
A-B=3x^2+4x-5 -(x^2-4x-1)
A-B=2x^2 + 8x - 4

find minimum value of A-B

The maximum or minimum of a quadratic function occurs at
x= -b/2a ...........in your case a=2, b=8
x= -8/(2*2)
x=-8/4
x=-2

 

[nycmathguy]

functions
A =3x^2+4x-5
B=x^2-4x-1
A-B=3x^2+4x-5 -(x^2-4x-1)
A-B=2x^2 + 8x - 4

find minimum value of A-B

The maximum or minimum of a quadratic function occurs at
x= -b/2a ...........in your case a=2, b=8
x= -8/(2*2)
x=-8/4
x=-2

Easier than it seems.