Answer:
A. -8 and 20
Step-by-step explanation:
I think your question is missed of key information, allow me to add in and hope it will fit the original one.
Consider the graph of the quadratic function y = [tex]\frac{1}{4}[/tex][tex]x^{2} - 3x - 40[/tex]
What are the roots of the function?
A. –8 and 20
B. –40 and –8
C. –8 and 8
D. –40 and 20
My answer:
Given the function:
y = [tex]\frac{1}{4}[/tex][tex]x^{2} - 3x - 40[/tex]
<=> y = [tex]x^{2} - 12x - 160[/tex]
Let convert to the factors form, the roots of the function must meet the following requirements:
- The two number that has the sum of 12 = -b
- The two number that has the product of -40 = c
In 4 possible answer, only –8 and 20 is possible because:
-8 + 20 = 12 = -b
-8*20 = -160 = c
So the factored form of the function is:
y = (x + 8)(x-20)
Hope it will find you well.
