A pebble drops from a balcony that is 80 feet above the ground. The pebble lands on the top of a sign that is 16 feet high. The
function y=80−16t2 represents the height y (in feet) of the pebble t seconds after dropping from the balcony. How many seconds does the pebble drop before hitting the sign? The pebble hits the sign after ______ seconds.
We have 5x-9 = Y= 2x+6 ⇒ 5x-9 = 2x+6 ⇒ (5x-2x)+ (-9+9) = (2x-2x)+ (6+9) ⇒ 3x= 15 ⇒ x=5 Plug x=5 in Y = 5x-9, we have Y= 5*(5)-9 ⇒ Y=16 (x,Y)= (5,16) Hope this would help :))