Question

What are the domain and range of f(x) = 4* – 8?

Answer 1

Answer:

domain: {x | x is a real number}

range: {y l y> -8}

Step-by-step explanation:

f(x) = 4x² – 8 is a parabola, a U shape.

Since the stretch factor, 4, is positive, it opens up, there it will have a minimum value, the lowest point in the parabola.

y > -8  because the minimum is -8.

Parabolas do not have restricted "x" values. "4" does not restrict x because it is the stretch factor, which determines how wide the parabola is.

Quadratic standard form:

f(x) = ax² + bx + c

"a" represents how wide the graph is. If it's negative it opens down, if it's positive it opens up.

"b", if written, tells you it is not centred on the y-axis. It is not written, so the vertex is on the y-axis.

"c" is the y-intercept. In this case, since b = 0, it is also the minimum value.