John's sister went shopping with him. she expected to spend $100 on clothes, but spent only $10. john wanted to her calculate the percent error, but he thinks he may have made a mistake. are his calculations below correct? why or why not?
{$100-$10}/90 =10/90 = 11%

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

Which of the statements about the graph of the function y = 2x are true? check all of the boxes that apply. the domain is all real numbers x because the exponent of 2 can be any real number when the x-values increases by 1 unit, the y-value multiplies by 2. the y-intercept is (0, 1). the graph never goes below the x-axis because powers of 2 are never negative. the range is all real numbers.

What is the 9th term in the geometric sequence described by this explicit formula? an=-6. (2)(n-1) apex