Three roots of the polynomial equation x4- 4x3 - 2x2 + 12x + 9 = 0 are 3. -1 and -1. Explain why the fourth root must be a real number. Find the fourth root.

Can someone explain this in a simple way??

In a probability experiment, karen flipped a coin 76 times. the coin landed on heads 32 times. what percentage of the coin flips resulted in tails? round to the nearest percent. a. 58% b. 65% c. 42% d. 60%

Do social recommendations increase ad effectiveness? a study of online video viewers compared viewers who arrived at an advertising video for a particular brand by following a social media recommendation link to viewers who arrived at the same video by web browsing. data were collected on whether the viewer could correctly recall the brand being advertised after seeing the video. the results are given below. correctly recalled the brandarrival 409153browsing20484b. conduct the hypothesis test, using the 0.025 level of significance. what is the value of the test statistic? χ2stat=what is the p-value? p-value=is this value significant atα=0.025?

Is there an x intercept in the equation 60*1.15^x