Find the distance between (1,8) and (-9,8) on the coordinate plane

Which equation requires the division property of equality to be solved?

Assume that y varies inversely with x. if y=1.6 when x=0.5 find x when y=3.2

Mallory has been offers two different jobs. she can baby sit for 6 hours a week and get $8.50 an hour. or she can work at the library for 14 hours a week and make $5.50 an hour. which job will allow her to save the most money after 6weeks?