A zero is an input where a polynomial meets the -axis. A curve that touches and turns needs an even-powered factor there; a curve that crosses needs an odd-powered factor. Use those factors to build a possible function, then use the -intercept to find its multiplier. Zeros alone can't distinguish functions with different multipliers.
Hints
- Hint 1
An -intercept is a point where the output is . The curve touches and turns at one intercept but crosses at the other. Which factor should be squared so the function doesn't change sign there?
- Hint 2
Put an unknown number in front of the factors. The -intercept gives the output when , so substitute into your expression. What must the number in front be to match the graph?
Step-by-step
Build the factors, then check the intercept
Step 1Match each factor to the graph's behavior
At , the curve touches and turns. The factor is there, so square it: doesn't change sign across . At , the curve crosses, so use once. Touching calls for an even-powered factor; crossing calls for an odd-powered factor.
- Step 2
Allow for a multiplier
Multiplying by a coefficient, a number out front, changes the curve's heights without moving those zeros. So among the choices, the matching factor pattern has the form . The unknown multiplier still matters: the factors alone don't tell you the height at .
- Step 3
Use the marked y-intercept
The graph passes through . A -intercept has input , so . Substitute for in the factored form: .
- Step 4
Find the multiplier and choose
Type in Desmos. Use for the unknown multiplier and to have Desmos fit its value. Under PARAMETERS, Desmos shows . So has the required intercept and factor pattern. Choice A.