What percent of normal distribution lies outside of -+3 standard deviation

In trapezoid klmn, kj=19.2 and jm=22.5. identify ln.

The variable z is directly proportional to x, and inversely proportional to y. when x is 4 and y is 13, z has the value 1.2307692307692. what is the value of z when x= 9, and y= 20

An equation of the line tangent to y=x^3+3x^2+2 at its point of inflection is