Answer:
is in proportion.
is not in proportion.
is in proportion.
is in proportion.
Step-by-step explanation:
The first example is and it is in proportion.
This is because, you will get the same simplest fraction (
) from the fraction 
by dividing its numerator and denominator by 5.
The second example is and it is not in proportion.
This is because, you can not get the simplest fraction (
) from the fraction 
after simplification.
The third example is and it is in proportion.
This is because, you will get the same simplest fraction (
) from the fraction 
by dividing its numerator and denominator by 2 and from the fraction 
by dividing its numerator and denominator by 3.
The fourth example is and it is in proportion.
This is because, you will get the same simplest fraction () from the fraction 
by dividing its numerator and denominator by 5. (Answer)
Answer:
1.
8x + 6y = 28
9x + 3y = 39
Set to equal y.
8x + 6y = 28
6y = -8x + 28
y = -8/6x + 28/6
y = -4/3x + 14/3
9x + 3y = 39
3y = -9x + 39
y = -9/3x + 39/3
y = -3x + 13
Set equal to each other.
-4/3x + 14/3 = -3x + 13
Combine like terms.
5/3x = 25/3
Multiply by 3/5
x = 5
Plug x in.
y = -3(5) + 13
y = -15 + 13
y = -2
(5, -2)
2.
-2x - 9y = -3
-7x - 9y= -33
Set equal to y.
-2x - 9y = -3
-9y = 2x - 3
y = -2/9x + 3/9
y = -2/9x + 1/3
-7x - 9y= -33
-9y = 7x - 33
y = -7/9x + 33/9
y = -7/9x + 11/3
Set equal to each other
-2/9x + 1/3 = -2/9x + 1/3
0 = 0
infinitely many solutions
Answer:
$90
Step-by-step explanation:
The shoes now cost 130% of the original cost
The original cost is 100%
Take the new amount and divide it by 130:
117/130 = .90
Then multiply that number by 100 to get the original percent
.90 x 100 = $90
To check, multiply $90 by 130% or 1.30 to make sure that a 30% increase makes the product $117
$90 x 1.30 = $117
