Standard form for (x--5)(x--1)

Question

(X--5)(x--1) in standard and vertex form 

Answer 1

Hi Jessalynn,

 

The standard form of a quadratic equation is

y = ax^2 + bx + c

If you multiply the binomials (x-5)(x-1) using FOIL rules, you should get

y = x^2 - 6x + 5. This is the standard form.

 

The vertex form of a quadratic equation can be written as 

y= a(x-h)^2 + k

h is the axis of symmetry and can be calculated by -b/2a

and we get h=-(-6)/2*1 = 3 (remember that we know a=1 and b=-6)

 

And k represents the value of the function when x=h

so plug in 3 for x and find the value of the function

y = x^2 - 6x + 5

= 3^2 - 6*3 + 5

= -4 (this is k)

now we know h and k, so the vertex form can be written as

y= 1(x-3)^2 - 4