Let $r$ be the set of primitive $42^{\text{nd}}$ roots of unity, and let $s$ be the set of primitive $70^{\text{th}}$ roots of unity. how many elements do $r$ and $s$ have in common?

Sadie computes the perimeter of a rectangle by adding the length, l, and width, w, and doubling this sum. eric computes the perimeter of a rectangle by doubling the length, l, doubling the width, w, and adding the doubled amounts. write an equation for sadie’s way of calculating the

The chs baseball team was on the field and the batter popped the ball up. the equation b(t)=80t-16•16+3.5 represents the height of the ball above the ground in feet as a function of time in seconds. how long will the catcher have to get in position to catch the ball before it hits the ground? round to the nearest second

Find the solution of this system of equation -7x+y=-20 9x-3y=36