Equation 1:
x = (5y+11)/2
Substitute equation 1 to 2:
-2((5y+11)/2)+ 3y=-9
-2/2 = -1 thus -1(5y+11)
Continue...
-(5y+11)+3y=-9
-5y-11+3y =-9
(-5+3)y= 11-9
-2y = 2
y=-1
Substitute y into equation 1:
x=(5*-1+11)/2
x = 6/2=3
So y=-1 and x =3
Part A
Your problem statement already shows you the conversion.
Bottles purchased: 5×10¹⁰
Bottles recycled: 8.3×10⁹
Part B
The ratio of bottles purchased to bottles recycled is
... (5×10¹⁰)/(8.3×10⁹) = 0.6×10¹ = 6.0
The number of bottles purchased is 6 times the number of bottles recycle.
1. yes, it is a proportional relationship
2. k=3
3. y=3x
4. 3
5.y=35x
6. y=7
hope this helps!
