She would have had to buy 8 key chains for three dollars a piece.
The system of linear equations that relates x and y:
x= 15 + y
5 x = 2 y+ 525
We will solve this system using substitution method:
5(15 + y)=2 y + 525
75 + 5 y = 2 y + 525
5 y - 2 y = 525 - 75
3 y = 450, y = 450 : 3 y = 150
x = 15 + y x = 15 + 150 x = 165
Answer: Aaron´s height is 165 cm and Peter´s height is 150 cm.
X=-3 because first substitute the value of y into the original equation -2x-3=x+6 then isolate the variables -2x-x=6+3 which is -3x=9 then we can divide x=9/-3 which =-3
