What is the range of the function f(x) = 3x2 + 6x – 8? y y y y

Question

What is the range of the function f(x) = 3x2 + 6x – 8?

y ≥ –1
y
y
y

Answer 1

The range of the function f(x) = 3x^2 + 6x - 8 is y ≥ –11

Answer 2

The range of the function f(x)=3x²+6x-8 is:

y

Explanation:

The function f(x)=3x²+6x-8 could also be written as:

f(x)=3x²+6x+3-11

f(x)=3(x²+2x+1)-11

f(x)=3(x+1)²-11

as we know that the value of 3(x+1)²≥0

Then, the value of 3(x+1)²-11≥-11

i.e. f(x)≥-11

Hence, the range of the function f(x)=3x²+6x-8 is:

y ≥ –11