You have 720 grams of a radioactive kind of tellurium. If its half-life is 70 minutes, how much will be left after 210 minutes

This is different from the first one can someone me

Find the slope and the y-intercept if there's one and the equation of the line given these two points( 3, 2) and( 3, -4)

The school that imani goes to is selling tickets to the annual dance competition. on the first day of the ticket sales the school sold 7 adult tickets and 5 child tickets for a total of $96. the school took in $40 on the second day by seling 3 adult tickets . find the price of an adult ticket and the price of a child ticket. solve by using substitution elimination college prep algebra math heres the 2 equations i came up with 7x+5y=96 and 3x+2y= -40 show all workiv be stuck on this.