Eryn and seven of her freinds go out to lunch the bill comes out 143.35 and they leave a 15% tip how much does each freind contribute

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?

Is the point (0, 8) on the x-axis or y-axis? how do you know?

The birth weights of newborn babies in the unites states follow in a normal distrubution with a mean of 3.4 kg and standard deviation of 0.6 kg. reaserches interested in studying how. children gain weights decide to take random samples of 100 newborn babies and calculate the sample mean birth weights for each sample