How do you know if a slope is undefined? What does a line look like with an undefined slope?

Help please 2 questionsASAP

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.

Aquadratic equation in standard from is written ax^2= bx+c, where a,b and c are real numbers and a is not zero?

Hey hotel charges guests $19.75 a day to rent five video games at this rate which expression can be used to determine the charge for renting nine video games for one day at this hotel? pls